Medium 6.9Published May 8, 2026

CVE-2026-41509Integer underflow in crypto_sign_open() leads to buffer overflow

Updated under an hour ago (Oct 27, 2026, 12:10 PM ET)

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It affects CROSS-signature CROSS-implementation and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for CROSS-signature CROSS-implementation

Exploited in the last 30 days

CROSS implementation contains reference and optimized implementations of the CROSS post-quantum signature algorithm. Prior to commit fc6b7e7, there is a buffer overflow in crypto_sign_open() caused by an underflow of the integer mlen. This issue has been patched via commit fc6b7e7.

CVSS: 6.9 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
Weakness (CWE): CWE-121, CWE-122
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: May 8, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

CROSS-signature CROSS-implementation cross_signature:cross_implementation (from the name)	before fc6b7e78cdf789bb5c395a81dc601356f1383da0	CNA record
cross-crypto cross-implementation cross-crypto:cross-implementation	before 2026-03-23	NVD

References

References

https://github.com/CROSS-signature/CROSS-implementation/security/advisories/GHSA-w72c-hgx8-p7cv	x-refsource-confirm, vendor-advisory
https://github.com/CROSS-signature/CROSS-implementation/commit/fc6b7e78cdf789bb5c395a81dc601356f1383da0	x-refsource-misc, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.