medium

CVE-2026-53720

PyPI · pymonocypher

Summary

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

Severity
medium
EPSS
0.1% (p3)
CWE
CWE-122, CWE-787, CWE-1284
Also known as
GHSA-8f95-v3jq-cj86
Published
2026-07-09
Updated
2026-07-09

Advisory details

Impact

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.

Patches

Fixed in 4.0.2.8, which now verifies that nb_blocks is large enough. See 90ff5b1.

Workarounds

Provide a correctly sized nb_blocks buffer.

pymonocypher thanks Haris (hextheshadow) for the vulnerability report, details, and recommended fix.

References

Related advisories

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Sources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.