CVE-2026-44519

MEDIUMPre-NVD 5.15.1
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 5.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1% (2nd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source

Also known asEUVD-2026-118513 (ENISA EUVD)Source: ENISA EUVD

5.1EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 5.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
5.1
EG Score
5.1MEDIUMmedium confidence
EG Risk
23
EG Risk 23/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity51% × 45%
Impact severity (EG Severity): CVSS 5.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.1%
EPSS %ILE
2nd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.1): severity, escalated by confirmed exploitation. This CVE's 5.1 is its impact severity (EG Severity), not escalated.

EG Severity
5.1 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

November 6, 2026

Last Modified

November 12, 2026

Advisory Details (4)

Auto-updated Nov 6, 2026
Patch available. Sources: github, github_commit, github_pr, github_release.
GitHub release Patch Available

liboqs version 0.16.0

Patch available: open-quantum-safe/liboqs 0.16.0

https://github.com/open-quantum-safe/liboqs/releases/tag/0.16.0
GitHub commit

commit d95fc734f5de (open-quantum-safe/liboqs)

Fix landed in open-quantum-safe/liboqs commit d95fc734f5de — awaiting tagged release

https://github.com/open-quantum-safe/liboqs/commit/d95fc734f5de9bdfc80c8c65d8166b30e9cff5cd
GitHub pull request

Implement value barrier and apply to FrodoKEM

Fix merged in open-quantum-safe/liboqs PR #2431 on 2026-06-18 — awaiting tagged release

https://github.com/open-quantum-safe/liboqs/pull/2431
GitHub advisoryMentions a patch (unverified)

Missing value barrier in FrodoKEM FO implicit rejection path · Advisory · open-quantum-safe/liboqs · GitHub

https://github.com/open-quantum-safe/liboqs/security/advisories/GHSA-5c97-hp95-vg56

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 8× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

  1. 2026-11-12 22:30 UTCEchelonGraph re-scored
  2. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  3. 2026-11-11 16:39 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  4. 2026-11-10 21:31 UTCEchelonGraph re-scored
  5. 2026-11-10 20:27 UTCEchelonGraph re-scored
  6. 2026-11-10 16:44 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  7. 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  8. 2026-11-08 16:39 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  9. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  10. 2026-11-06 22:27 UTCEchelonGraph re-scored
  11. 2026-11-06 22:04 UTCENISA EUVD ID recordedEUVD-2026-118513 · Source: ENISA EUVD
  12. 2026-11-06 21:26 UTCEchelonGraph re-scoredFirst assessed: 5.1 MEDIUM
  13. 2026-11-06 21:26 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-44519?
CVE-2026-44519 is a medium-severity vulnerability; its CVE record was published on November 6, 2026. 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…
When was the CVE record for CVE-2026-44519 published?
The CVE record for CVE-2026-44519 was published on November 6, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of November 12, 2026; the record at its source may have been updated since.
Is CVE-2026-44519 actively exploited?
CVE-2026-44519 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (2nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-44519?
CVE-2026-44519 has a CVSS base score of 5.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-44519?
A fix for CVE-2026-44519 is available: update to the fixed version the vendor names in its advisory.

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