{"id":"CVE-2026-118768","kind":"vulnerability","aliases":["CVE-2026-118768"],"related":[],"title":"Botan: OCSP check accepts unsigned responses, so revoked certificates pass","description":"Botan is a C++ cryptography library. From 1.11.34 until 3.13.0, the botan ocsp_check command requested an OCSP response from a certificate's Authority Information Access URL without verifying the response signature or authorizing the signer. A malicious responder or on-path attacker could return a matching and timely GOOD response with an empty, invalid, or unauthorized signature, causing a revoked certificate to produce exit status 0 and OCSP check OK output. Only the command-line interface is affected. This issue is fixed in version 3.13.0.","summary":"The botan ocsp_check command accepted OCSP responses without verifying their signature, so a revoked certificate could be reported as good. An attacker who can answer the OCSP request or sit on the network path can make a revoked certificate look valid.","severity":"medium","cvss":5.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["botan","c++","cryptography","ocsp","package"],"not_affected_if":["library-only-use","no-ocsp-check-command"],"how_to_check":"- Run `botan version` and see whether it reports a version earlier than `3.13.0`.\n- Search build and deployment scripts for `ocsp_check` use.","fix":"- Botan: upgrade to `3.13.0`.","status":"open","published_at":"2026-10-29T18:17:28+00:00","first_seen_at":"2026-10-29T18:26:33+00:00","triaged_at":"2026-10-29T18:28:42+00:00","updated_at":"2026-10-29T18:28:42+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-29T18:28:42Z","model":"claude-haiku-5-5","output":{"fix":"- Botan: upgrade to `3.13.0`.","reach":"network","title":"Botan: OCSP check accepts unsigned responses, so revoked certificates pass","impact":"medium","summary":"The botan ocsp_check command accepted OCSP responses without verifying their signature, so a revoked certificate could be reported as good. An attacker who can answer the OCSP request or sit on the network path can make a revoked certificate look valid.","audience":"developers","category":"package","nicknames":[],"who_cares":["botan","c++","cryptography","ocsp"],"confidence":0.7,"fix_status":"available","needs_auth":"no","worst_case":"revoked certificates wrongly reported as valid by the CLI","analyst_note":"","how_to_check":"- Run `botan version` and see whether it reports a version earlier than `3.13.0`.\n- Search build and deployment scripts for `ocsp_check` use.","plain_action":"","needs_analyst":false,"not_affected_if":["library-only-use","no-ocsp-check-command"],"who_is_affected":"Only the botan command-line tool's ocsp_check command is affected, per the description; library use outside that command is not described as affected. Teams that run ocsp_check to decide whether a certificate is revoked are the ones relying on the wrong result. Teams that do not invoke this command can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000668,"input_tokens":4181,"output_tokens":499,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-118768':13A,16A '-2026':12A,15A '0':131C '1.11.34':71C '3.13.0':73C,151C 'accept':4A,27B 'access':89C 'affect':144C 'answer':47B 'attack':44B,107C 'author':87C,97C 'botan':1A,17B,23B,64C,75C 'c':18B,67C 'caus':123C 'certif':9A,37B,61B,85C,126C 'check':3A,25B,77C,134C 'command':26B,78C,140C 'command-lin':139C 'could':38B,108C 'cryptographi':19B,68C 'cve':11A,14A 'empti':118C 'exit':129C 'fix':148C 'good':42B,114C 'inform':88C 'interfac':142C 'invalid':119C 'issu':146C 'librari':69C 'line':141C 'look':62B 'make':58B 'malici':101C 'match':111C 'network':55B 'ocsp':2A,20B,24B,28B,49B,76C,81C,133C 'ok':135C 'on-path':104C 'output':136C 'packag':21B 'pass':10A 'path':56B,106C 'produc':128C 'report':40B 'request':50B,79C 'respond':102C 'respons':6A,29B,82C,94C,115C 'return':109C 'revok':8A,36B,60B,125C 'signatur':33B,95C,122C 'signer':99C 'sit':52B 'status':130C 'time':113C 'unauthor':121C 'unsign':5A 'url':90C 'valid':63B 'verifi':31B,92C 'version':150C 'without':30B,91C","nicknames":[],"mitigations":[],"who_affected":"Only the botan command-line tool's ocsp_check command is affected, per the description; library use outside that command is not described as affected. Teams that run ocsp_check to decide whether a certificate is revoked are the ones relying on the wrong result. Teams that do not invoke this command can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"first_public_at":"2026-10-29T18:17:28+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/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":"security-advisories@github.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-118768","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118768","severity":null,"published_at":"2026-10-29T18:17:28+00:00","modified_at":"2026-10-29T18:17:28+00:00","first_seen_at":"2026-10-29T18:26:33+00:00","fetched_at":"2026-10-29T18:26:33+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"}