CVE-2026-74901 json
openssl_encrypt before 1.4.0 Authentication Bypass via AES-CTR Fallback
published 9mo ago modified last mo. also EUVD-2026-60118 , GHSA-w4j7-wfgw-r52w , PYSEC-2026-3773
- cvss
- 9.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 35%
- public exploits
- 0
- none known
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 integrity verification and perform bit-flipping attacks without detection.
Patch / fix
- pypi openssl-encrypt 1.4.0
- jahlives openssl_encrypt 1.4.0
Is CVE-2026-74901 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
- Assessed
- 2mo ago
Exploit prediction
0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 9.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| CNA | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| CNA | 4.0 | 9.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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 |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | openssl-encrypt | <1.4.0 |
1.4.0 |
Affected products
- jahlives openssl_encrypt
Classification
- Weakness
-
- CWE-347 Improper Verification of Cryptographic Signature
References
-
github.com
/jahlives/openssl_encrypt/security/advisories/GHSA-w4j7-wfgw-r52w
vendor-advisory, mitigation, advisory
-
vulncheck.com
/advisories/openssl-encrypt-before-authentication-bypass-via-aes-ctr-fallback
third-party-advisory, advisory
Sources
- CVE List CVE-2026-74901
- NVD CVE-2026-74901
- OSV PYSEC-2026-3773
- Maintainer advisory GHSA-w4j7-wfgw-r52w
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
The maintainers of jahlives/openssl_encrypt published their own advisory on GitHub. Reviewed sources take precedence over it.