{"id":"GHSA-fc39-fwh3-wv5r","kind":"vulnerability","aliases":["GHSA-fc39-fwh3-wv5r"],"related":[],"title":"CVE-2026-125926 - Server-side request forgery in the server registration and update API in mcp-gateway-registry","description":"CVE-2026-125926 - Server-side request forgery in the server registration and update API in mcp-gateway-registry\n\n### CVE-2026-125926 - Server-side request forgery in the server registration and update API in mcp-gateway-registry\n\nBulletin ID: 2026-180-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 11/11/2026 13:00 PM PST\n\n Description:\n\nmcp-gateway-registry is an open-source registry and gateway for Model Context Protocol (MCP) servers that centralizes discovery, access control, and proxying of registered MCP tool assets. We identified CVE-2026-125926, a server-side request forgery issue in how the registry validates the upstream address of a registered server.\n\nAn authenticated user with permission to register or modify a server could configure an upstream address that caused the gateway to send requests to services on the deployment's internal network. In some cases the gateway returned those responses to the user.\n\nImpacted versions: >= v1.0.3 AND <= 1.34.0\n\nResolution:\n\nThis issue has been addressed in mcp-gateway-registry version 1.35.0. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.\n\nNote on version sequencing: a separate and unrelated issue in this product's external management API was addressed in version 1.25.0. A deployment running 1.25.0 or later carries that fix, but remains affected by the issue described here until it runs version 1.35.0 or later.\n\nPost-upgrade actions:\n\nVersion 1.35.0 validates server upstream addresses when a server is registered or modified. It leaves server configurations stored before the upgrade unchanged. Customers who ran an affected version should take the following steps after upgrading:\n\n1. Review the upstream addresses of registered servers, and correct or remove any address you did not intend.\n2. Review application logs from the period an affected version was deployed for unexpected server registrations and changes.\n3. If the registry runs with an attached cloud role and the log review cannot rule out unexpected activity, review that role's activity and rotate its credentials.\n\nWorkarounds:\n\nThe following measures limit risk for deployments that cannot yet upgrade. They do not replace the post-upgrade actions above:\n\n- Limit the permission to register and modify servers to trusted accounts.\n- Restrict outbound network access from the registry and auth-server components to the destinations they need.\n- On Amazon EC2, require IMDSv2. Grant the role attached to each component only the permissions it needs.\n\nReferences:\n\n- CVE-2026-125926\n- GHSA-fc39-fwh3-wv5r\n\nAcknowledgement:\n\nWe would like to thank the external researcher (handle novice-22) for collaborating on this issue through the coordinated disclosure process.\n\n Please email aws-security@amazon.com with any s ecurity questions or concerns.","summary":"The MCP gateway registry lets a user who can register or modify a server set an upstream address that the gateway then requests, including services on the deployment's internal network. In some cases the gateway returns those responses to the user, so internal data can leak.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"mcp-gateway-registry","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["ai-tooling","aws","ec2","lab-disclosure","mcp","self-hosted"],"not_affected_if":["no-internal-network-services","trusted-registrars-only","version-1.35.0-or-later"],"how_to_check":"- Check the installed `mcp-gateway-registry` version; versions `>= 1.0.3` and `<= 1.34.0` are affected.\n- Review the upstream addresses of registered servers for any address you did not intend.\n- Review application logs for unexpected server registrations and changes.","fix":"- `mcp-gateway-registry` `1.35.0` or later; this version validates upstream addresses on registration and modification, but does not change server configurations stored before the upgrade.\n- Also review existing stored upstream addresses after upgrading.","status":"open","published_at":"2026-11-11T00:00:00+00:00","first_seen_at":"2026-11-11T21:28:41+00:00","triaged_at":"2026-11-11T21:31:01+00:00","updated_at":"2026-11-11T21:31:01+00:00","category":"ai-tooling","confidence":0.8,"triage":{"at":"2026-11-11T21:31:01Z","model":"claude-haiku-5-5","output":{"fix":"- `mcp-gateway-registry` `1.35.0` or later; this version validates upstream addresses on registration and modification, but does not change server configurations stored before the upgrade.\n- Also review existing stored upstream addresses after upgrading.","reach":"network","title":"mcp-gateway-registry: authenticated users can make the gateway reach internal services","impact":"medium","summary":"The MCP gateway registry lets a user who can register or modify a server set an upstream address that the gateway then requests, including services on the deployment's internal network. In some cases the gateway returns those responses to the user, so internal data can leak.","audience":"businesses","category":"ai-tooling","nicknames":[],"who_cares":["mcp","self-hosted","aws","ec2"],"confidence":0.8,"fix_status":"available","needs_auth":"yes","worst_case":"internal network services reached and some responses returned to the user","analyst_note":"","how_to_check":"- Check the installed `mcp-gateway-registry` version; versions `>= 1.0.3` and `<= 1.34.0` are affected.\n- Review the upstream addresses of registered servers for any address you did not intend.\n- Review application logs for unexpected server registrations and changes.","plain_action":"","product_name":"mcp-gateway-registry","needs_analyst":false,"not_affected_if":["version-1.35.0-or-later","trusted-registrars-only","no-internal-network-services"],"who_is_affected":"Deployments of mcp-gateway-registry at version 1.0.3 through 1.34.0 are exposed, especially where users other than trusted administrators can register or change MCP servers. The risk is greatest when the registry or auth-server runs on a network with internal services or on Amazon EC2 with an attached cloud role. Deployments on 1.35.0 or later are not affected by this issue, though stored configurations from before the upgrade need review.","user_interaction":"no","product_ecosystem":"vendor","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000893,"input_tokens":5465,"output_tokens":694,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-125926':3A,96C,116C,188C,507C '-180':137C '-2026':2A,95C,115C,187C,506C '-22':524C '00':150C '1':373C '1.25.0':309C,313C '1.34.0':254C '1.35.0':267C,331C,339C '11/11/2026':148C '13':149C '2':391C '2026':136C '3':409C 'access':175C,473C 'account':469C 'acknowledg':513C 'action':337C,457C 'activ':427C,432C 'address':64B,203C,223C,260C,306C,343C,377C,386C 'affect':321C,364C,399C 'ai':36B 'ai-tool':35B 'amazon':488C 'api':15A,108C,128C,304C 'applic':393C 'asset':183C 'attach':416C,495C 'attent':145C 'auth':479C 'auth-serv':478C 'authent':209C 'aw':38B,138C,140C 'aws-security@amazon.com':537C 'bulletin':134C 'cannot':423C,446C 'carri':316C 'case':80B,241C 'caus':225C 'central':173C 'chang':408C 'cloud':417C 'code':281C 'collabor':526C 'compon':481C,498C 'concern':544C 'configur':220C,354C 'content':141C 'context':168C 'control':176C 'coordin':532C 'correct':382C 'could':219C 'credenti':436C 'custom':360C 'cve':1A,94C,114C,186C,505C 'data':91B 'date':147C 'deploy':74B,235C,311C,402C,444C 'deriv':280C 'describ':325C 'descript':153C 'destin':484C 'disclosur':42B,533C 'discoveri':174C 'ec2':39B,489C 'ecur':541C 'email':536C 'ensur':276C 'extern':302C,520C 'fc39':23A,28A,510C 'fix':288C,318C 'follow':369C,439C 'forgeri':8A,101C,121C,194C 'fork':278C 'fwh3':24A,29A,511C 'gateway':19A,33A,49B,67B,82B,112C,132C,156C,165C,227C,243C,264C 'ghsa':22A,27A,509C 'ghsa-fc39-fwh3-wv5r':21A,26A,508C 'grant':492C 'handl':522C 'host':46B 'id':135C 'identifi':185C 'imdsv2':491C 'impact':250C 'import':143C 'includ':70B 'incorpor':285C 'intend':390C 'intern':76B,90B,237C 'issu':195C,257C,297C,324C,529C 'lab':41B 'lab-disclosur':40B 'later':315C,333C 'latest':273C 'leak':93B 'leav':352C 'let':51B 'like':516C 'limit':441C,459C 'log':394C,421C 'manag':303C 'mcp':18A,32A,43B,48B,111C,131C,155C,170C,181C,263C 'mcp-gateway-registri':17A,110C,130C,154C,262C 'mcp-gateway-registry':31A 'measur':440C 'model':167C 'modifi':58B,216C,350C,465C 'need':486C,503C 'network':77B,238C,472C 'new':287C 'note':289C 'novic':523C 'open':161C 'open-sourc':160C 'outbound':471C 'patch':283C 'period':397C 'permiss':212C,461C,501C 'pleas':535C 'pm':151C 'post':335C,455C 'post-upgrad':334C,454C 'process':534C 'product':300C 'protocol':169C 'proxi':178C 'pst':152C 'public':146C 'question':542C 'ran':362C 'recommend':269C 'refer':504C 'regist':56B,180C,206C,214C,348C,379C,463C 'registr':12A,105C,125C,406C 'registri':20A,50B,113C,133C,157C,163C,199C,265C,412C,476C 'registry':34A 'remain':320C 'remov':384C 'replac':452C 'request':7A,69B,100C,120C,193C,230C 'requir':144C,490C 'research':521C 'resolut':255C 'respons':85B,246C 'restrict':470C 'return':83B,244C 'review':374C,392C,422C,428C 'risk':442C 'role':418C,430C,494C 'rotat':434C 'rule':424C 'run':312C,329C,413C 'scope':139C 'self':45B 'self-host':44B 'send':229C 'separ':294C 'sequenc':292C 'server':5A,11A,60B,98C,104C,118C,124C,171C,191C,207C,218C,341C,346C,353C,380C,405C,466C,480C 'server-sid':4A,97C,117C,190C 'servic':71B,232C 'set':61B 'side':6A,99C,119C,192C 'sourc':162C 'step':370C 'store':355C 'take':367C 'thank':518C 'tool':37B,182C 'trust':468C 'type':142C 'unchang':359C 'unexpect':404C,426C 'unrel':296C 'updat':14A,107C,127C 'upgrad':270C,336C,358C,372C,448C,456C 'upstream':63B,202C,222C,342C,376C 'user':53B,88B,210C,249C 'v1.0.3':252C 'valid':200C,340C 'version':251C,266C,274C,291C,308C,330C,338C,365C,400C 'workaround':437C 'would':515C 'wv5r':25A,30A,512C 'yet':447C","nicknames":[],"mitigations":[],"who_affected":"Deployments of mcp-gateway-registry at version 1.0.3 through 1.34.0 are exposed, especially where users other than trusted administrators can register or change MCP servers. The risk is greatest when the registry or auth-server runs on a network with internal services or on Amazon EC2 with an attached cloud role. Deployments on 1.35.0 or later are not affected by this issue, though stored configurations from before the upgrade need review.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":["mcpgatewayregistry"],"ptokens":["gateway","mcp","registry"],"labels":["aitooling","aws","ec2","labdisclosure","mcp","selfhosted","unknown","vendor"],"campaign_type":null,"search_a":"'-125926':3A '-2026':2A 'api':15A 'cve':1A 'fc39':23A,28A 'forgeri':8A 'fwh3':24A,29A 'gateway':19A,33A 'ghsa':22A,27A 'ghsa-fc39-fwh3-wv5r':21A,26A 'mcp':18A,32A 'mcp-gateway-registri':17A 'mcp-gateway-registry':31A 'registr':12A 'registri':20A 'registry':34A 'request':7A 'server':5A,11A 'server-sid':4A 'side':6A 'updat':14A 'wv5r':25A,30A","search_b":"'address':64B 'ai':36B 'ai-tool':35B 'aw':38B 'case':80B 'data':91B 'deploy':74B 'disclosur':42B 'ec2':39B 'gateway':49B,67B,82B 'host':46B 'includ':70B 'intern':76B,90B 'lab':41B 'lab-disclosur':40B 'leak':93B 'let':51B 'mcp':43B,48B 'modifi':58B 'network':77B 'regist':56B 'registri':50B 'request':69B 'respons':85B 'return':83B 'self':45B 'self-host':44B 'server':60B 'servic':71B 'set':61B 'tool':37B 'upstream':63B 'user':53B,88B","search_c":"'-125926':96C,116C,188C,507C '-180':137C '-2026':95C,115C,187C,506C '-22':524C '00':150C '1':373C '1.25.0':309C,313C '1.34.0':254C '1.35.0':267C,331C,339C '11/11/2026':148C '13':149C '2':391C '2026':136C '3':409C 'access':175C,473C 'account':469C 'acknowledg':513C 'action':337C,457C 'activ':427C,432C 'address':203C,223C,260C,306C,343C,377C,386C 'affect':321C,364C,399C 'amazon':488C 'api':108C,128C,304C 'applic':393C 'asset':183C 'attach':416C,495C 'attent':145C 'auth':479C 'auth-serv':478C 'authent':209C 'aw':138C,140C 'aws-security@amazon.com':537C 'bulletin':134C 'cannot':423C,446C 'carri':316C 'case':241C 'caus':225C 'central':173C 'chang':408C 'cloud':417C 'code':281C 'collabor':526C 'compon':481C,498C 'concern':544C 'configur':220C,354C 'content':141C 'context':168C 'control':176C 'coordin':532C 'correct':382C 'could':219C 'credenti':436C 'custom':360C 'cve':94C,114C,186C,505C 'date':147C 'deploy':235C,311C,402C,444C 'deriv':280C 'describ':325C 'descript':153C 'destin':484C 'disclosur':533C 'discoveri':174C 'ec2':489C 'ecur':541C 'email':536C 'ensur':276C 'extern':302C,520C 'fc39':510C 'fix':288C,318C 'follow':369C,439C 'forgeri':101C,121C,194C 'fork':278C 'fwh3':511C 'gateway':112C,132C,156C,165C,227C,243C,264C 'ghsa':509C 'ghsa-fc39-fwh3-wv5r':508C 'grant':492C 'handl':522C 'id':135C 'identifi':185C 'imdsv2':491C 'impact':250C 'import':143C 'incorpor':285C 'intend':390C 'intern':237C 'issu':195C,257C,297C,324C,529C 'later':315C,333C 'latest':273C 'leav':352C 'like':516C 'limit':441C,459C 'log':394C,421C 'manag':303C 'mcp':111C,131C,155C,170C,181C,263C 'mcp-gateway-registri':110C,130C,154C,262C 'measur':440C 'model':167C 'modifi':216C,350C,465C 'need':486C,503C 'network':238C,472C 'new':287C 'note':289C 'novic':523C 'open':161C 'open-sourc':160C 'outbound':471C 'patch':283C 'period':397C 'permiss':212C,461C,501C 'pleas':535C 'pm':151C 'post':335C,455C 'post-upgrad':334C,454C 'process':534C 'product':300C 'protocol':169C 'proxi':178C 'pst':152C 'public':146C 'question':542C 'ran':362C 'recommend':269C 'refer':504C 'regist':180C,206C,214C,348C,379C,463C 'registr':105C,125C,406C 'registri':113C,133C,157C,163C,199C,265C,412C,476C 'remain':320C 'remov':384C 'replac':452C 'request':100C,120C,193C,230C 'requir':144C,490C 'research':521C 'resolut':255C 'respons':246C 'restrict':470C 'return':244C 'review':374C,392C,422C,428C 'risk':442C 'role':418C,430C,494C 'rotat':434C 'rule':424C 'run':312C,329C,413C 'scope':139C 'send':229C 'separ':294C 'sequenc':292C 'server':98C,104C,118C,124C,171C,191C,207C,218C,341C,346C,353C,380C,405C,466C,480C 'server-sid':97C,117C,190C 'servic':232C 'side':99C,119C,192C 'sourc':162C 'step':370C 'store':355C 'take':367C 'thank':518C 'tool':182C 'trust':468C 'type':142C 'unchang':359C 'unexpect':404C,426C 'unrel':296C 'updat':107C,127C 'upgrad':270C,336C,358C,372C,448C,456C 'upstream':202C,222C,342C,376C 'user':210C,249C 'v1.0.3':252C 'valid':200C,340C 'version':251C,266C,274C,291C,308C,330C,338C,365C,400C 'workaround':437C 'would':515C 'wv5r':512C 'yet':447C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-11T00:00:00+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"lab","external_id":"https://aws.amazon.com/security/security-bulletins/2026-180-aws/#GHSA-fc39-fwh3-wv5r","url":"https://aws.amazon.com/security/security-bulletins/2026-180-aws/","severity":null,"published_at":"2026-11-11T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-11-11T21:28:41+00:00","fetched_at":"2026-11-11T21:28:41+00:00","note":"AWS: CVE-2026-125926 - Server-side request forgery in the server registration and update API in mcp-gateway-registry"}],"documents":[{"id":128949,"url":"https://aws.amazon.com/security/security-bulletins/2026-180-aws/","title":"AWS: CVE-2026-125926 - Server-side request forgery in the server registration and update API in mcp-gateway-registry","kind":"advisory","source":"lab","publisher":"research","text":"CVE-2026-125926 - Server-side request forgery in the server registration and update API in mcp-gateway-registry\n\n### CVE-2026-125926 - Server-side request forgery in the server registration and update API in mcp-gateway-registry\n\nBulletin ID: 2026-180-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 11/11/2026 13:00 PM PST\n\n Description:\n\nmcp-gateway-registry is an open-source registry and gateway for Model Context Protocol (MCP) servers that centralizes discovery, access control, and proxying of registered MCP tool assets. We identified CVE-2026-125926, a server-side request forgery issue in how the registry validates the upstream address of a registered server.\n\nAn authenticated user with permission to register or modify a server could configure an upstream address that caused the gateway to send requests to services on the deployment's internal network. In some cases the gateway returned those responses to the user.\n\nImpacted versions: >= v1.0.3 AND <= 1.34.0\n\nResolution:\n\nThis issue has been addressed in mcp-gateway-registry version 1.35.0. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.\n\nNote on version sequencing: a separate and unrelated issue in this product's external management API was addressed in version 1.25.0. A deployment running 1.25.0 or later carries that fix, but remains affected by the issue described here until it runs version 1.35.0 or later.\n\nPost-upgrade actions:\n\nVersion 1.35.0 validates server upstream addresses when a server is registered or modified. It leaves server configurations stored before the upgrade unchanged. Customers who ran an affected version should take the following steps after upgrading:\n\n1. Review the upstream addresses of registered servers, and correct or remove any address you did not intend.\n2. Review application logs from the period an affected version was deployed for unexpected server registrations and changes.\n3. If the registry runs with an attached cloud role and the log review cannot rule out unexpected activity, review that role's activity and rotate its credentials.\n\nWorkarounds:\n\nThe following measures limit risk for deployments that cannot yet upgrade. They do not replace the post-upgrade actions above:\n\n- Limit the permission to register and modify servers to trusted accounts.\n- Restrict outbound network access from the registry and auth-server components to the destinations they need.\n- On Amazon EC2, require IMDSv2. Grant the role attached to each component only the permissions it needs.\n\nReferences:\n\n- CVE-2026-125926\n- GHSA-fc39-fwh3-wv5r\n\nAcknowledgement:\n\nWe would like to thank the external researcher (handle novice-22) for collaborating on this issue through the coordinated disclosure process.\n\n Please email aws-security@amazon.com with any s ecurity questions or concerns.","published_at":"2026-11-11T00:00:00+00:00","relation":"advisory","confidence":null,"note":null}],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}