{"id":"CVE-2021-21311","kind":"vulnerability","aliases":["CVE-2021-21311"],"related":[],"title":"Adminer is an open-source database management in a single PHP file","description":"Adminer contains a server-side request forgery vulnerability that, when exploited, allows a remote attacker to obtain potentially sensitive information.\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":"Adminer, a PHP database administration tool, has a server-side request forgery flaw. A remote attacker can make the server send requests to internal addresses and read back potentially sensitive information.","severity":"high","cvss":7.2,"epss":null,"exploited":true,"exploited_at":"2025-09-29T00:00:00+00:00","products":[{"name":"Adminer Adminer","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"adminer","fixed":["4.7.9"],"affected":">= 4.0.0, < 4.7.9","ecosystem":"vendor"},{"name":"debian linux","fixed":[],"affected":"= 9.0","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["adminer","exploited","other","php","self-hosted"],"not_affected_if":["default-config"],"how_to_check":null,"fix":"Upgrade Adminer to a fixed release per vendor instructions; the sources do not name the fixed version. Discontinue use if no mitigation is available, per CISA.","status":"open","published_at":"2021-02-11T21:15:13+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T20:44:49+00:00","updated_at":"2026-10-23T23:44:51+00:00","category":"other","confidence":0.5,"triage":{"at":"2026-10-23T20:44:49Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade Adminer to a fixed release per vendor instructions; the sources do not name the fixed version. Discontinue use if no mitigation is available, per CISA.","reach":"internet","summary":"Adminer, a PHP database administration tool, has a server-side request forgery flaw. A remote attacker can make the server send requests to internal addresses and read back potentially sensitive information.","category":"other","who_cares":["adminer","php","self-hosted"],"confidence":0.5,"needs_auth":"unknown","worst_case":"Remote attacker reaches internal services through the server and reads sensitive data.","analyst_note":"Exploited in the wild per CISA KEV; find the affected and fixed Adminer versions and exact exploitation preconditions in the Adminer advisory or NVD entry for CVE-2021-21311.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["default-config"],"user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000431,"input_tokens":2523,"output_tokens":357,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-01':97C '-2021':15A,18A '-21311':16A,19A '22':96C 'action':87C 'address':57B 'admin':1A,25B,32B,64C 'adminer':20A,21A,22A 'administr':36B 'allow':76C 'appli':88C 'applic':94C 'attack':48B,79C 'back':60B 'bod':95C 'cisa':85C 'cloud':100C 'contain':65C 'cve':14A,17A 'databas':7A,35B 'debian':23A 'discontinu':103C 'exploit':26B,75C 'file':13A 'flaw':45B 'follow':93C 'forgeri':44B,71C 'guidanc':98C 'host':31B 'inform':63B,84C 'instruct':92C 'intern':56B 'linux':24A 'make':50B 'manag':8A 'mitig':89C,109C 'obtain':81C 'open':5A 'open-sourc':4A 'per':90C 'php':12A,28B,34B 'potenti':61B,82C 'product':107C 'read':59B 'remot':47B,78C 'request':43B,54B,70C 'requir':86C 'self':30B 'self-host':29B 'send':53B 'sensit':62B,83C 'server':41B,52B,68C 'server-sid':40B,67C 'servic':101C 'side':42B,69C 'singl':11A 'sourc':6A 'tool':37B 'unavail':111C 'use':104C 'vendor':91C 'vulner':72C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-02-11T21:15:13+00:00","kev":{"dateAdded":"2025-09-29","dueDate":"2025-10-20","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:L/PR:N/UI:N/S:C/C:L/I:L/A:N","cvss_by":"security-advisories@github.com","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-21311","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-21311","severity":null,"published_at":"2025-09-29T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:51+00:00","fetched_at":"2026-10-25T10:39:04+00:00","note":null},{"source":"nvd","external_id":"CVE-2021-21311","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21311","severity":null,"published_at":"2021-02-11T21:15:13+00:00","modified_at":"2026-06-17T03:35:16+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"}