CVE-2026-41509

CRITICAL 9.8CVE-2026-41509 · Published 08/05/2026 · updated 26/10/2026

In short

CVE-2026-41509 is a CRITICAL (CVSS 9.8) vulnerability affecting cross-implementation (cross-crypto).
Chance of exploitation in the next 30 days (EPSS): 0.34%, higher than 27.4% of all vulnerabilities.
Fix: update to 2026-03-23 or later.

Package	Affected versions	Patched versions
cross-implementation cross-crypto	`< 2026-03-23`	`2026-03-23`

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.

References

CROSS-signature/CROSS-implementation commit fc6b7e7 · Patch
CROSS-signature/CROSS-implementation security advisory · Vendor Advisory

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