CVE-2026-53720

pymonocypher: Potential heap buffer overflow on nb_blocks in argon2i_32 when provided buffer is too small

State: Published
Severity: 5.1 Medium
Published: Sep 3, 2026
Updated: Sep 3, 2026
Reserved: Jun 10, 2026

Description

pymonocypher uses cython to wrap the Monocypher C library. Prior to version 4.0.2.8, the argon2i_32 implementation does not check the nb_blocks size. If the caller does not provide a sufficiently large buffer based on the API contract, then argon2i_32 will write past the end of the buffer and possibly corrupt the heap. This issue has been patched in version 4.0.2.8.

Scores

CVSS	Score	Vector	Source
4.0	5.1 Medium	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-122 Heap-based Buffer Overflow
CWE-787 Out-of-bounds Write
CWE-1284 Improper Validation of Specified Quantity in Input

Affected Products

Product	Versions
pymonocypherjetperch	< 4.0.2.8Affected

References

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