CVE-2026-41509

Description

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 v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0006

Probability of exploitation

0.19%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-121 CWE-121

CWE-122 CWE-122

Affected Products

Vendor	Product	Versions
cross-crypto	cross-implementation	< 2026-03-23

References

Advisories & Patches

https://github.com/CROSS-signature/CROSS-implementation/commit/fc6b7e78cdf789bb5c395a81dc601356f1383da0 https://github.com/CROSS-signature/CROSS-implementation/security/advisories/GHSA-w72c-hgx8-p7cv

Frequently Asked Questions

What is CVE-2026-41509? +

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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-41509? +

CVE-2026-41509 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0006, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-41509? +

CVE-2026-41509 affects products from cross-crypto, specifically: cross-implementation. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-41509? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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