PYSEC-2026-3773

vendorUSosv

view advisory published 2026-08-17Licence: CC-BY-4.0

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.

describes (1)

Related CVEs.

ID	severity	EPSS	exploitable	published
CVE-2026-74901US	—	0.40% (35th)	—	2026-08-17
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. A…

references

External citations — patches, advisories, analysis.

https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-w4j7-wfgw-r52wADVISORY
https://www.vulncheck.com/advisories/openssl-encrypt-before-authentication-bypass-via-aes-ctr-fallbackADVISORY

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