Is there a public exploit for CVE-2026-104254?

No public exploit for CVE-2026-104254 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-104254?

CVE-2026-104254 scores CVSS 5.3 (v3.1), rated medium.

What does CVE-2026-104254 affect?

CVE-2026-104254 affects open-quantum-safe liboqs.

5.3 Medium

liboqs is a C-language cryptographic library that provides implementations of post-quantum cryptography algorithms.

CVE-2026-104254

liboqs is a C-language cryptographic library that provides implementations of post-quantum cryptography algorithms. From 0.11.0 through 0.16.0, builds configured with OQSENABLESIGSTFLLMS=ON can read beyond a caller-supplied signature buffer when an untrusted truncated LMS or HSS-LMS signature reaches OQSSIGSTFLverify or OQSSIGSTFLalglmsverify. In hssvalidatesignatureinit() in src/sigstfl/lms/external/hssverifyinc.c, consumed-length checks do not ensure that the bottom-level q and C fields remain available, allowing up to 32 bytes to be read past the buffer. In version 0.16.0, ishsspublickey() also reads at offset 8 after only a four-byte length check, allowing an over-read of up to eight bytes. No valid signature is required, but the public key must be syntactically plausible. The read data is consumed only by an internal hash and is not exposed, so the supported impact is a possible verifier crash and denial of service, not memory disclosure or acceptance of an invalid signature. This issue is scheduled to be fixed in version 0.17.0.

Assessment

CVSS: 5.3 (v3.1)
Severity: Medium
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 6 November 2026
Last updated: 6 November 2026
Affected: open-quantum-safe · liboqs
Assigner: GitHub_M

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

At the source

EUVD (ENISA)

References

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