CVE-2026-44519
liboqs: Missing value barrier in FO implicit rejection path (FrodoKEM, NTRU, and others)
- 5.1MediumCVSS base score
- 0.12%Exploitation in 30 daysEPSS · top 98% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
liboqs is a C-language cryptographic library that provides implementations of post-quantum cryptography algorithms. Prior to 0.16.0, the ct_select function in src/kem/frodokem/external/util.c for the FrodoKEM-640, FrodoKEM-976, and FrodoKEM-1344 AES and SHAKE reference variants lacks a value barrier in the Fujisaki-Okamoto implicit-rejection path. When compiled with Clang 17 or later at an affected optimization level such as -Os, the compiler can emit a secret-dependent conditional load, causing the real and rejection secret paths to leave distinguishable cache residency after successful and failed decapsulation. A local attacker able to perform repeated cache-timing measurements may use this oracle as part of a private-key recovery attack. Default -O3 builds vectorize both source loads and do not exhibit the reported behavior, and the advisory does not report the same generated memory-access pattern in NTRU, NTRU-Prime, BIKE, HQC, Classic McEliece, Kyber, or the already-barriered ML-KEM implementation. This issue is fixed in version 0.16.0.
Timeline
ID reserved
By GitHub_M
- 6 months later
· 6 months later
Published
- 4 days later
· 4 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium5.1 | CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
| NVDNVD · Received | 3.1 | Medium5.1 | CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.12% · top 98% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.1.
Affected products
- affected < 0.16.0
References
References4
- https://github.com/open-quantum-safe/liboqs/security/advisories/GHSA-5c97-hp95-vg56 (opens in a new tab)x_refsource_CONFIRM
- https://github.com/open-quantum-safe/liboqs/pull/2431 (opens in a new tab)x_refsource_MISC
- https://github.com/open-quantum-safe/liboqs/commit/d95fc734f5de9bdfc80c8c65d8166b30e9cff5cd (opens in a new tab)x_refsource_MISC
- https://github.com/open-quantum-safe/liboqs/releases/tag/0.16.0 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-118513 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-44519)Record last updated .