{"id":"CVE-2026-74901","title":"openssl_encrypt before 1.4.0 Authentication Bypass via AES-CTR Fallback","summary":"openssl_encrypt versions before 1.4.0 contain an authentication bypass vulnerability in pqc.py where AES-GCM decryption failures trigger fallback to unauthenticated AES-CTR mode. Attackers can modify ciphertext in transit to bypass integ…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-347"],"vendor":"jahlives","product":"openssl_encrypt","affected":["openssl_encrypt < 1.4.0"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-08-17T16:00:48.847551Z"},"published":"2026-08-17","updated":"2026-10-01","sourceUpdated":"2026-10-01T15:21:06.550Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74901","references":[{"url":"https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-w4j7-wfgw-r52w","label":"GitHub Security Advisory (GHSA-w4j7-wfgw-r52w)"},{"url":"https://www.vulncheck.com/advisories/openssl-encrypt-before-authentication-bypass-via-aes-ctr-fallback","label":"VulnCheck Advisory: openssl_encrypt before 1.4.0 Authentication Bypass via AES-CTR Fallback"}],"tags":["cve.org","osv","pip"],"epss":0.00405,"epssPercentile":0.34536,"aliases":["PYSEC-2026-3773","GHSA-w4j7-wfgw-r52w"],"ecosystem":"pip","patched":["openssl-encrypt 1.4.0"],"ingestedAt":"2026-09-02T19:31:25.950Z","slug":"CVE-2026-74901","body":"## Overview\n\nopenssl_encrypt versions before 1.4.0 contain an authentication bypass vulnerability in pqc.py where AES-GCM decryption failures trigger fallback to unauthenticated AES-CTR mode. Attackers can modify ciphertext in transit to bypass integrity verification and perform bit-flipping attacks without detection.\n\n## Affected\n\n- `openssl_encrypt < 1.4.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-74901)\n\nAffected packages:\n\n- `openssl-encrypt < 1.4.0`\n\nPatched in:\n\n- `openssl-encrypt 1.4.0`\n\nSource: https://osv.dev/vulnerability/PYSEC-2026-3773","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":214431,"id":"CVE-2026-74901","ts":1790869823180,"field":"cvss","old":null,"new":"9.8"},{"seq":214430,"id":"CVE-2026-74901","ts":1790869823180,"field":"severity","old":"none","new":"critical"}]}