CVSS 3.1
5.3 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LCVE-2026-104254
Medium (5.3) in open-quantum-safe liboqs. EPSS 0.3% estimated probability of exploitation activity in the next 30 days.
On this page
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.
Severity
- EPSS
- 0.3% estimated probability of exploitation activity in the next 30 days; 22nd percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: yes · Technical impact: partial, assessed 2026-11-09. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-125 Out-of-bounds Read
- Published
- Assigned by
- GitHub_M (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
Ask an AI about this CVE
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Explain CVE-2026-104254 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-104254?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-104254?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-104254 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| open-quantum-safe liboqs | >= 0.11.0, <= 0.16.0 |
Attack patterns (CAPEC)
- CAPEC-540 Overread Buffers Likelihood: Low · Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.