CVE-2026-53720

MEDIUMPre-NVD 0.0
0.0
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No confirmed exploitation signals yet
CISA-KEV: Not listedEPSS: —CVSS: —Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

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.

CVSS v3
—
EG Score
0.0(none)
EG Risk
0
EG Risk 0/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses intrinsic severity with real-world exploitation and automatability, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. It is distinct from the 0–10 EG Score, which measures severity.

EPSS
—
KEV
Not listed

Published

July 9, 2026

Last Modified

July 9, 2026

Vendor Advisories for CVE-2026-53720(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
pymonocypher0.1.1 ... 4.0.2.7 (19 versions)4.0.2.8—

Data Freshness Timeline

(refreshed 1× in last 7d / 2× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 03:19 UTCEG score recompute
  2. 2026-07-09 13:45 UTCEG score recompute

Frequently asked(3)

What is CVE-2026-53720?
CVE-2026-53720 is a medium vulnerability published on July 9, 2026. pymonocypher: Potential heap buffer overflow on nbblocks in argon2i32 when provided buffer is too small Impact The argon2i32 implementation does not check the nbblocks size. If the caller does not provide a sufficiently large buffer based on the API contract, then argon2i_32 will write past the end…
When was CVE-2026-53720 disclosed?
CVE-2026-53720 was first published in the National Vulnerability Database on July 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
How do I remediate CVE-2026-53720?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53720, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-53720

Explore →

Is Your Infrastructure Affected by CVE-2026-53720?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs