CVE-2026-44699

CRITICALNVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 89% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this weekElevated
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

LibJWT is a C JSON Web Token Library. From 3.0.0 to 3.3.2, libjwt accepts an RSA JWK that does not contain an alg parameter as the verification key for an HS256/HS384/HS512 token. In the OpenSSL backend, this causes HMAC verification to run with a zero-length key, so an attacker can forge a valid JWT without knowing any secret or RSA private key. This is an algorithm-confusion authentication bypass. It affects applications that load RSA keys from JWKS where alg is omitted, which is valid JWK syntax and common in real deployments, and then choose the verification algorithm from the JWT header, for example in a kid lookup callback. This vulnerability is fixed in 3.3.3.

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
57(Track*)
EG Risk 57/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
11.2%
KEV
Not listed

Published

May 15, 2026

Last Modified

May 18, 2026

Advisory Details (1)

Auto-updated May 15, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Algorithm confusion allows JWT forgery with RSA JWK as empty-key HMAC · Advisory · benmcollins/libjwt · GitHub

https://github.com/benmcollins/libjwt/security/advisories/GHSA-q843-6q5f-w55g

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 33× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 14:18 UTCEPSS rescore
  2. 2026-07-23 03:15 UTCEG score recompute
  3. 2026-07-22 14:08 UTCEPSS rescore
  4. 2026-07-21 15:24 UTCEPSS rescore
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  9. 2026-07-18 00:59 UTCOSV refresh
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  1. 2026-06-29 14:06 UTCEPSS rescore
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  5. 2026-06-27 03:08 UTCEPSS rescore
  6. 2026-06-25 13:49 UTCEPSS rescore
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  9. 2026-06-23 21:33 UTCEPSS rescore
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  18. 2026-06-17 17:53 UTCEPSS rescore
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  20. 2026-06-15 17:49 UTCEPSS rescore
  21. 2026-06-13 23:00 UTCEPSS rescore
  22. 2026-06-12 23:12 UTCEPSS rescore
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  25. 2026-06-10 22:18 UTCEPSS rescore
  26. 2026-06-10 13:22 UTCEPSS rescore
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  28. 2026-06-08 14:17 UTCEPSS rescore
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  30. 2026-06-07 15:25 UTCEPSS rescore
  31. 2026-06-07 15:25 UTCEPSS rescore
  32. 2026-06-06 13:47 UTCEPSS rescore
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  35. 2026-06-05 06:10 UTCEPSS rescore
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  37. 2026-06-04 13:12 UTCEPSS rescore
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  39. 2026-06-02 20:13 UTCEPSS rescore
  40. 2026-06-01 13:52 UTCEPSS rescore
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  42. 2026-05-31 22:30 UTCEPSS rescore
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  44. 2026-05-29 13:44 UTCEPSS rescore
  45. 2026-05-29 13:44 UTCEPSS rescore
  46. 2026-05-28 13:44 UTCEPSS rescore
  47. 2026-05-28 13:44 UTCEPSS rescore
  48. 2026-05-27 13:40 UTCEPSS rescore
  49. 2026-05-27 13:40 UTCEPSS rescore
  50. 2026-05-26 13:44 UTCEPSS rescore
  51. 2026-05-26 07:18 UTCEPSS rescore
  52. 2026-05-21 22:43 UTCEPSS rescore
  53. 2026-05-20 22:38 UTCEPSS rescore
  54. 2026-05-20 12:02 UTCEG score recompute
  55. 2026-05-20 11:22 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2026-44699?
CVE-2026-44699 is a critical vulnerability published on May 15, 2026. LibJWT is a C JSON Web Token Library. From 3.0.0 to 3.3.2, libjwt accepts an RSA JWK that does not contain an alg parameter as the verification key for an HS256/HS384/HS512 token. In the OpenSSL backend, this causes HMAC verification to run with a zero-length key, so an attacker can forge a valid…
When was CVE-2026-44699 disclosed?
CVE-2026-44699 was first published in the National Vulnerability Database on May 15, 2026, with the most recent update on May 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-44699 actively exploited?
CVE-2026-44699 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 11.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-44699?
CVE-2026-44699 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-44699?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-44699, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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