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TI-2026-86140 Aliases CVE-2026-104254

Out-of-bounds read in liboqs LMS/HSS signature verification

Priority LOW 24CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · None · Low
Fix status
No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

liboqs from 0.11.0 through 0.16.0 is affected when built with OQS_ENABLE_SIG_STFL_LMS=ON. Missing length checks in LMS/HSS signature verification let a truncated signature cause reads up to 32 bytes past the caller's buffer (CWE-125). An unauthenticated remote attacker who supplies a truncated signation with a syntactically plausible public key can trigger a possible verifier crash and denial of service, but the read data is not exposed.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

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.

Why it matters now

EPSS 0.00291 21st percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
open-quantum-safeliboqs0.11.0 – 0.16.0—No fix listedCNA
  • liboqs Vendoropen-quantum-safe Affected 0.11.0 – 0.16.0 Fixed in — No fix listed CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:openquantumsafe:liboqs:*:*:*:*:*:*:*:*——open-quantum-safe
  • cpe:2.3:a:openquantumsafe:liboqs:*:*:*:*:*:*:*:* Versions — — ·open-quantum-safe

Remediation

The sources list no fixed version for liboqs. The source description states that this issue is scheduled to be fixed in version 0.17.0.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Timeline

  1. 2026-11-06 Threatist record created from CVE-2026-104254

References

  • TI-2024-20867 An issue in Open Quantum Safe liboqs v.10.0 allows a remote attacker to escalate… CVSS 3.1CRITICAL 9.8
  • TI-2024-24817 Buffer overflow in deserialization in oqs-provider CVSS 3.1HIGH 8.2
  • TI-2024-36253 liboqs has a correctness error in HQC decapsulation CVSS 3.1HIGH 7.5
  • TI-2024-24191 Control-flow timing leak in Kyber reference implementation when compiled with Clang 15-18 for -Os, -O1 and other options CVSS 3.1HIGH 7.5
  • TI-2026-34064 liboqs: Heap-buffer-overflow in XMSS verification path via OID-controlled parameter mismatch (xmss_commons.c:194) CVSS 3.1MEDIUM 5.3
  • TI-2026-32448 liboqs: XMSS Buffer Overread Bug CVSS 3.1MEDIUM 5.3
See all 10 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences