CVE-2026-104254 PUBLISHED

liboqs: Heap out-of-bounds read in LMS/HSS signature verification via unvalidated signature length (hss_verify_inc.c:215)

Assigner: GitHub_M
Reserved: 01.10.2026 Published: 06.11.2026 Updated: 06.11.2026

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 OQS_ENABLE_SIG_STFL_LMS=ON can read beyond a caller-supplied signature buffer when an untrusted truncated LMS or HSS-LMS signature reaches OQS_SIG_STFL_verify or OQS_SIG_STFL_alg_lms_verify. In hss_validate_signature_init() in src/sig_stfl/lms/external/hss_verify_inc.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, is_hss_public_key() 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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS Score: 5.3

Product Status

Vendor open-quantum-safe
Product liboqs
Versions
  • Version >= 0.11.0, <= 0.16.0 is affected

References

Problem Types

  • CWE-125: Out-of-bounds Read CWE