PYSEC-2026-3772

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Import Source
https://github.com/pypa/advisory-database/blob/main/vulns/openssl-encrypt/PYSEC-2026-3772.yaml
JSON Data
https://api.osv.dev/v1/vulns/PYSEC-2026-3772
Aliases
Published
2026-08-17T11:16:45.050Z
Modified
2026-09-02T09:00:05.029715670Z
Severity
  • 9.3 (Critical) CVSS_V4 - 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 CVSS Calculator
Summary
[none]
Details

openssl_encrypt versions before 1.4.0 contain a critical vulnerability in pqc.py where KEM decapsulation failures silently fall back to simulation mode, generating a deterministic shared secret from only 16 bytes of the private key and publicly available encapsulated key data. Attackers who obtain 16 bytes of the private key can compute the shared secret and decrypt all ciphertext, as the fallback triggers on any KEM failure without raising an error.

References

Affected packages

PyPI / openssl-encrypt

Package

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.4.0

Affected versions

0.*
0.2.2
0.2.3
0.2.4
0.2.5
0.2.6
0.3.0
0.3.1
0.3.2
0.3.3
0.4.0
0.4.1
0.4.2
0.4.3
0.4.4
0.5.0
0.5.1
0.5.3
0.6.0rc1
0.7.0rc2
0.7.1
0.7.2
0.8.0
0.8.1
0.8.2
0.9.2
1.*
1.0.0
1.0.1
1.0.2
1.0.3
1.1.0
1.2.0
1.2.1
1.3.0
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
1.4.0b3
1.4.0b4
1.4.0b5
1.4.0b6
1.4.0b7
1.4.0b8

Database specific

source
"https://github.com/pypa/advisory-database/blob/main/vulns/openssl-encrypt/PYSEC-2026-3772.yaml"