{"id":"CVE-2026-123125","kind":"vulnerability","aliases":["CVE-2026-123125"],"related":[],"title":"Symfony Validator: Ip constraint accepts some internal addresses, enabling SSRF","description":"The Symfony Validator component IpValidator incompletely classifies internal addresses in the filtered modes of the Ip constraint, so some internal addresses are accepted as public, which can lead to Server-Side Request Forgery (SSRF) in Symfony versions prior to 5.4.56, 6.x prior to 6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.\n\nIn these modes, IpValidator relies on the PHP flags FILTER_FLAG_NO_PRIV_RANGE and FILTER_FLAG_NO_RES_RANGE to classify addresses as public, private, or reserved. These flags do not cover shared address space (100.64.0.0/10) or IPv4-mapped, IPv4-compatible, and 6to4 IPv6 addresses, which can embed internal IPv4 addresses. A value such as ::ffff:127.0.0.1 can therefore pass validation even though it points to an internal host.\nApplications that rely on the Ip constraint to reject internal addresses, for example before making a server-side request to a user-supplied address, can be exposed to SSRF.","summary":"The Symfony Validator's Ip constraint, in its filtered modes, fails to classify shared-space and embedded IPv4 addresses (such as ::ffff:127.0.0.1) as internal, so they pass as public. An attacker who supplies a URL or address that the application then requests can reach internal hosts, a server-side request forgery.","severity":"medium","cvss":6.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["package","php","ssrf","symfony","web-apps"],"not_affected_if":["no-ip-constraint","no-user-supplied-urls","static-export"],"how_to_check":"- Run `composer show symfony/validator` and compare the version to the fixed releases.\n- Search the codebase for `new Ip(` or `#[Assert\\Ip(` used with filtered modes such as `Ip::PRIVATE_NETWORK`, `Ip::PUBLIC_ONLY` or `Ip::ALL_NO_RES`, and check whether it guards outbound requests.","fix":"- symfony/validator 5.4 series: upgrade to `5.4.56`\n- symfony/validator 6.x: upgrade to `6.4.50`\n- symfony/validator 7.x: upgrade to `7.4.23`\n- symfony/validator 8.x: upgrade to `8.1.11`","status":"open","published_at":"2026-11-05T16:17:46+00:00","first_seen_at":"2026-11-05T16:40:02+00:00","triaged_at":"2026-11-05T16:41:41+00:00","updated_at":"2026-11-05T16:41:41+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-05T16:41:41Z","model":"claude-haiku-5-5","output":{"fix":"- symfony/validator 5.4 series: upgrade to `5.4.56`\n- symfony/validator 6.x: upgrade to `6.4.50`\n- symfony/validator 7.x: upgrade to `7.4.23`\n- symfony/validator 8.x: upgrade to `8.1.11`","reach":"internet","title":"Symfony Validator: Ip constraint accepts some internal addresses, enabling SSRF","impact":"medium","summary":"The Symfony Validator's Ip constraint, in its filtered modes, fails to classify shared-space and embedded IPv4 addresses (such as ::ffff:127.0.0.1) as internal, so they pass as public. An attacker who supplies a URL or address that the application then requests can reach internal hosts, a server-side request forgery.","audience":"developers","category":"package","nicknames":[],"who_cares":["symfony","php","ssrf","web-apps"],"confidence":0.7,"fix_status":"available","needs_auth":"unknown","worst_case":"Attacker reaches internal services through the server, possibly reading internal data.","analyst_note":"","how_to_check":"- Run `composer show symfony/validator` and compare the version to the fixed releases.\n- Search the codebase for `new Ip(` or `#[Assert\\Ip(` used with filtered modes such as `Ip::PRIVATE_NETWORK`, `Ip::PUBLIC_ONLY` or `Ip::ALL_NO_RES`, and check whether it guards outbound requests.","plain_action":"","needs_analyst":false,"not_affected_if":["no-ip-constraint","no-user-supplied-urls","static-export"],"who_is_affected":"Applications that use the Symfony Ip constraint in filtered modes to decide whether a user-supplied address is internal before the server requests it are exposed. Applications that do not use the Ip constraint for this purpose, or that do not make server-side requests to user-supplied addresses, are not affected by the SSRF path.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000814,"input_tokens":4529,"output_tokens":722,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-123125':13A,16A '-2026':12A,15A '/10':172C '100.64.0.0':171C '127.0.0.1':47B,195C '5.4.56':118C '6':119C '6.4.50':123C '6to4':181C '7':124C '7.4.23':128C '8':130C '8.1.11':134C 'accept':5A,100C 'address':8A,43B,62B,86C,98C,157C,169C,183C,189C,218C,233C 'app':23B 'applic':65B,208C 'attack':56B 'classifi':36B,84C,156C 'compat':179C 'compon':81C 'constraint':4A,29B,94C,214C 'cover':167C 'cve':11A,14A 'emb':186C 'embed':41B 'enabl':9A 'even':200C 'exampl':220C 'expos':236C 'fail':34B 'ffff':46B,194C 'filter':32B,89C,144C,150C 'flag':143C,145C,151C,164C 'forgeri':77B,111C 'host':71B,207C 'incomplet':83C 'intern':7A,49B,70B,85C,97C,187C,206C,217C 'ip':3A,28B,93C,213C 'ipv4':42B,175C,178C,188C 'ipv4-compatible':177C 'ipv4-mapped':174C 'ipv6':182C 'ipvalid':82C,138C 'lead':105C 'make':222C 'map':176C 'mode':33B,90C,137C 'packag':17B 'pass':52B,198C 'php':18B,142C 'point':203C 'prior':116C,121C,126C,132C 'priv':147C 'privat':160C 'public':54B,102C,159C 'rang':148C,154C 'reach':69B 'reject':216C 'reli':139C,210C 'request':67B,76B,110C,227C 'res':153C 'reserv':162C 'server':74B,108C,225C 'server-sid':73B,107C,224C 'share':38B,168C 'shared-spac':37B 'side':75B,109C,226C 'space':39B,170C 'ssrf':10A,19B,112C,238C 'suppli':58B,232C 'symfoni':1A,20B,25B,79C,114C 'therefor':197C 'though':201C 'url':60B 'user':231C 'user-suppli':230C 'valid':2A,26B,80C,199C 'valu':191C 'version':115C 'web':22B 'web-app':21B 'x':120C,125C,131C","nicknames":[],"mitigations":[],"who_affected":"Applications that use the Symfony Ip constraint in filtered modes to decide whether a user-supplied address is internal before the server requests it are exposed. Applications that do not use the Ip constraint for this purpose, or that do not make server-side requests to user-supplied addresses, are not affected by the SSRF path.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["medium","package","php","ssrf","symfony","webapps"],"campaign_type":null,"first_public_at":"2026-11-04T11:43:57+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"596c5446-0ce5-4ba2-aa66-48b3b757a647","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-123125","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-123125","severity":null,"published_at":"2026-11-05T16:17:46+00:00","modified_at":"2026-11-05T16:17:46+00:00","first_seen_at":"2026-11-05T16:40:02+00:00","fetched_at":"2026-11-05T16:40:02+00:00","note":null}],"documents":[{"id":77647,"url":"https://github.com/symfony/symfony/commit/3bf8ea37fcb402c5ecc502a3f63012df85a7572e","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":77648,"url":"https://github.com/symfony/symfony/security/advisories/GHSA-4qpf-57w4-m3wc","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-11-04T11:43:57+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"}],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}