by Kastro
Paper/Archive/CVE-2026-74901

CVE-2026-74901

jahlives openssl_encrypt — openssl_encrypt before 1.4.0 Authentication Bypass via AES-CTR Fallback

EPSS 0.4%CVSS 9.8
critical.is priorityof 100
36
CVSS 9.8 (CNA)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 34.7.347 × 206.9No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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 integrity verification and perform bit-flipping attacks without detection.

Affected

ProductAffectedFixed inSource
openssl_encrypt< 1.4.01.4.0CNA

Scores by source

VulnCheck (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
VulnCheck (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

advisorygithub.com/jahlives/openssl_encrypt/security/advisories/GHSA-w4j7-wfgw-r52wwriteupvulncheck.com/advisories/openssl-encrypt-before-authentication-bypass-via-aes-ctr-fallback