{"id":"CVE-2021-39935","kind":"vulnerability","aliases":["CVE-2021-39935"],"related":[],"title":"An issue has been discovered in GitLab CE/EE affecting all versions starting from 10.5 before 14.3.6, all versions…","description":"GitLab Community and Enterprise Editions contain a server-side request forgery vulnerability which could allow unauthorized external users to perform Server Side Requests via the CI Lint API.\n\nCISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","summary":"GitLab Community and Enterprise Editions have a server-side request forgery flaw in the CI Lint API. An unauthenticated external attacker can make the GitLab server send requests to internal or external destinations of their choosing.","severity":"high","cvss":7.5,"epss":null,"exploited":true,"exploited_at":"2026-02-03T00:00:00+00:00","products":[{"name":"GitLab Community and Enterprise Editions","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"gitlab","fixed":["14.3.6"],"affected":">= 10.5.0, < 14.3.6","ecosystem":"vendor"},{"name":"gitlab","fixed":["14.4.4"],"affected":">= 14.4.0, < 14.4.4","ecosystem":"vendor"},{"name":"gitlab","fixed":["14.5.2"],"affected":">= 14.5.0, < 14.5.2","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","gitlab","package","self-hosted"],"not_affected_if":["managed-hosting"],"how_to_check":null,"fix":"Apply the mitigations and upgrade to the fixed GitLab version per vendor instructions; the sources do not name the fixed version.","status":"open","published_at":"2021-12-13T16:15:09+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T20:42:28+00:00","updated_at":"2026-10-23T23:44:51+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-23T20:42:28Z","model":"claude-haiku-5-5","output":{"fix":"Apply the mitigations and upgrade to the fixed GitLab version per vendor instructions; the sources do not name the fixed version.","reach":"internet","summary":"GitLab Community and Enterprise Editions have a server-side request forgery flaw in the CI Lint API. An unauthenticated external attacker can make the GitLab server send requests to internal or external destinations of their choosing.","category":"package","who_cares":["gitlab","self-hosted"],"confidence":0.6,"needs_auth":"no","worst_case":"Attacker reaches internal services from the GitLab server, possibly reading internal data.","analyst_note":"Find the fixed GitLab versions and the vendor mitigation steps for the CI Lint API from the GitLab advisory linked in the CVE record, and confirm whether CI Lint is reachable without auth on default configs.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["managed-hosting"],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000439,"input_tokens":2567,"output_tokens":364,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-01':117C '-2021':20A,23A '-39935':21A,24A '10.5':14A '14.3.6':16A '22':116C 'action':107C 'affect':9A 'allow':91C 'and':27A 'api':56B,104C 'appli':108C 'applic':114C 'attack':60B 'bod':115C 'ce/ee':8A 'choos':75B 'ci':54B,102C 'cisa':105C 'cloud':120C 'communiti':40B,77C 'community':26A 'contain':81C 'could':90C 'cve':19A,22A 'destin':72B 'discontinu':123C 'discov':5A 'edit':43B,80C 'editions':29A 'enterpris':42B,79C 'enterprise':28A 'exploit':33B 'extern':59B,71B,93C 'flaw':51B 'follow':113C 'forgeri':50B,87C 'gitlab':7A,25A,30A,31A,32A,34B,39B,64B,76C 'guidanc':118C 'host':38B 'instruct':112C 'intern':69B 'issu':2A 'lint':55B,103C 'make':62B 'mitig':109C,129C 'packag':35B 'per':110C 'perform':96C 'product':127C 'request':49B,67B,86C,99C 'requir':106C 'self':37B 'self-host':36B 'send':66B 'server':47B,65B,84C,97C 'server-sid':46B,83C 'servic':121C 'side':48B,85C,98C 'start':12A 'unauthent':58B 'unauthor':92C 'unavail':131C 'use':124C 'user':94C 'vendor':111C 'version':11A,18A 'via':100C 'vulner':88C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-12-13T16:15:09+00:00","kev":{"dateAdded":"2026-02-03","dueDate":"2026-02-24","requiredAction":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N","cvss_by":"cve@gitlab.com","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-39935","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-39935","severity":null,"published_at":"2026-02-03T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:51+00:00","fetched_at":"2026-10-25T11:39:14+00:00","note":null},{"source":"nvd","external_id":"CVE-2021-39935","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-39935","severity":null,"published_at":"2021-12-13T16:15:09+00:00","modified_at":"2026-06-17T04:04:27+00:00","first_seen_at":"2026-10-23T23:44:51+00:00","fetched_at":"2026-10-23T23:44:51+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}