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Medium · 5.1 CVE-2026-53720 EUVD-2026-70531GHSA-8f95-v3jq-cj86PYSEC-2026-3000

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

Published Sep 3, 2026 · Updated Sep 3, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
jetperch pymonocypher < 4.0.2.8 —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI pymonocypher < 4.0.2.8 4.0.2.8 GHSA-8f95-v3jq-cj86

References