CVE-2026-53720

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

Published Sep 3, 2026 CVSS 4.0 · 5.1 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-8f95-v3jq-cj86 pymonocypher: Potential heap buffer overflow on nb_blocks in argon2i_32 when provided buffer is too small
History
Type Values Removed Values Added
First Time appeared Jetperch
Jetperch pymonocypher
Vendors & Products Jetperch
Jetperch pymonocypher
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title pymonocypher: Potential heap buffer overflow on nb_blocks in argon2i_32 when provided buffer is too small
Weaknesses CWE-122
CWE-1284
CWE-787
References
Metrics cvssV4_0

{'score': 5.1, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 3, 2026, 3:42 PM
Reserved
Jun 10, 2026, 4:43 PM
Status
Deferred
Published
Sep 3, 2026, 4:17 PM
Modified
Sep 9, 2026, 9:09 PM