CVE-2026-27962

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 57% 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, secondary
Trending — 3 sources updated this weekElevated
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.1Exploit: Elevated riskExposed: 0

A fix is available — apply it.

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a JWK Header Injection vulnerability in authlib's JWS implementation allows an unauthenticated attacker to forge arbitrary JWT tokens that pass signature verification. When key=None is passed to any JWS deserialization function, the library extracts and uses the cryptographic key embedded in the attacker-controlled JWT jwk header field. An attacker can sign a token with their own private key, embed the matching public key in the header, and have the server accept the forged token as cryptographically valid — bypassing authentication and authorization entirely. This issue has been patched in version 1.6.9.

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
72(Attend)
EG Risk 72/100SSVC: Attend

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%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
44%
KEV
Not listed

Published

March 16, 2026

Last Modified

August 17, 2026

Advisory Details (11)

Auto-updated Aug 1, 2026
🔬 Proof of concept available. Patch available. Sources: redhat, github_commit, github_release, github.
redhat

2448164 – (CVE-2026-27962) CVE-2026-27962 authlib: Authlib: Authentication bypass due to JWK Header Injection vulnerability

https://bugzilla.redhat.com/show_bug.cgi?id=2448164
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-27962
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:7314
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:5665
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:48085
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:24853
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:19375
github Patch Available🟡 PoC Available

JWS JWK Header Injection: Signature Verification Bypass · Advisory · authlib/authlib · GitHub

https://github.com/authlib/authlib/security/advisories/GHSA-wvwj-cvrp-7pv5
github_release Patch Available

v1.6.9

Patch available: authlib/authlib v1.6.9

https://github.com/authlib/authlib/releases/tag/v1.6.9
github_commit Patch Available

commit a5d4b2d4c9e4 (authlib/authlib)

Patch available: authlib/authlib v1.6.9 (contains commit a5d4b2d4c9e4)

https://github.com/authlib/authlib/commit/a5d4b2d4c9e46bfa11c82f85fdc2bcc0b50ae681
redhat Patch Available
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27962.json

Vendor Advisories for CVE-2026-27962(5)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(5)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatquay/quay-rhel9:17849872732026-07-29redhat
redhatquay/quay-rhel8:17808913952026-06-09redhat
redhatquay/quay-rhel9:17792040862026-05-19redhat
redhatquay/quay-rhel8:17755121632026-04-09redhat
redhatquay/quay-rhel8:17739710772026-03-24redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
python-authlib0.15.4-1, 0.15.4-1+deb11u10.15.4-1+deb11u2—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
python-authlib1.2.0-1, 1.2.0-1+deb12u11.2.0-1+deb12u2—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
python-authlib1.6.0-1 ... 1.7.2-2 (13 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
python-authlib1.6.0-1 ... 1.6.8-1 (8 versions)1.6.9-1—
PyPI(1)
PackageVulnerable rangeFixed inDependents
authlib0.1 ... 1.6.8 (56 versions)1.6.9—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 15× in last 7d / 88× 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.

Showing the most recent 100 of 128 total refreshes for this CVE.

  1. 2026-08-20 22:55 UTCEPSS rescore
  2. 2026-08-19 17:03 UTCEPSS rescore
  3. 2026-08-18 13:48 UTCEPSS rescore
  4. 2026-08-17 13:47 UTCEPSS rescore
  5. 2026-08-17 12:21 UTCEG score recompute
  6. 2026-08-17 12:21 UTCVendor advisory
  7. 2026-08-17 12:13 UTCEG score recompute
  8. 2026-08-17 12:13 UTCVendor advisory
  9. 2026-08-16 14:56 UTCEPSS rescore
  10. 2026-08-16 11:24 UTCEG score recompute
  11. 2026-08-16 11:24 UTCVendor advisory
  12. 2026-08-16 02:14 UTCEPSS rescore
  13. 2026-08-15 01:30 UTCEPSS rescore
  14. 2026-08-14 23:44 UTCVendor advisory
  15. 2026-08-14 19:59 UTCVendor advisory
  16. 2026-08-14 15:02 UTCVendor advisory
  17. 2026-08-14 11:14 UTCVendor advisory
  18. 2026-08-14 07:30 UTCEG score recompute
  19. 2026-08-14 07:30 UTCVendor advisory
  20. 2026-08-13 22:00 UTCEPSS rescore
  21. 2026-08-13 02:03 UTCVendor advisory
  22. 2026-08-12 22:17 UTCEG score recompute
  23. 2026-08-12 22:17 UTCVendor advisory
  24. 2026-08-12 13:50 UTCEPSS rescore
  25. 2026-08-12 12:39 UTCEG score recompute
Show 75 more
  1. 2026-08-12 12:39 UTCVendor advisory
  2. 2026-08-12 12:14 UTCEG score recompute
  3. 2026-08-12 12:14 UTCVendor advisory
  4. 2026-08-12 01:20 UTCVendor advisory
  5. 2026-08-11 21:35 UTCEG score recompute
  6. 2026-08-11 21:35 UTCVendor advisory
  7. 2026-08-11 13:42 UTCEPSS rescore
  8. 2026-08-11 08:38 UTCVendor advisory
  9. 2026-08-11 04:42 UTCEG score recompute
  10. 2026-08-11 04:42 UTCVendor advisory
  11. 2026-08-11 00:00 UTCEPSS rescore
  12. 2026-08-10 12:15 UTCVendor advisory
  13. 2026-08-10 08:13 UTCVendor advisory
  14. 2026-08-10 04:28 UTCVendor advisory
  15. 2026-08-10 00:38 UTCVendor advisory
  16. 2026-08-09 20:53 UTCVendor advisory
  17. 2026-08-09 17:09 UTCEG score recompute
  18. 2026-08-09 17:09 UTCVendor advisory
  19. 2026-08-09 13:46 UTCEPSS rescore
  20. 2026-08-09 13:24 UTCVendor advisory
  21. 2026-08-09 07:06 UTCEG score recompute
  22. 2026-08-09 07:06 UTCVendor advisory
  23. 2026-08-08 16:37 UTCEPSS rescore
  24. 2026-08-08 08:43 UTCVendor advisory
  25. 2026-08-08 04:58 UTCVendor advisory
  26. 2026-08-08 01:13 UTCVendor advisory
  27. 2026-08-07 21:28 UTCVendor advisory
  28. 2026-08-07 17:43 UTCEG score recompute
  29. 2026-08-07 17:43 UTCVendor advisory
  30. 2026-08-06 19:35 UTCEG score recompute
  31. 2026-08-06 19:35 UTCVendor advisory
  32. 2026-08-06 13:46 UTCEPSS rescore
  33. 2026-08-06 09:22 UTCVendor advisory
  34. 2026-08-06 05:29 UTCVendor advisory
  35. 2026-08-06 01:44 UTCEG score recompute
  36. 2026-08-06 01:44 UTCVendor advisory
  37. 2026-08-05 19:17 UTCEPSS rescore
  38. 2026-08-04 15:10 UTCEPSS rescore
  39. 2026-08-04 04:40 UTCVendor advisory
  40. 2026-08-04 00:56 UTCEG score recompute
  41. 2026-08-04 00:56 UTCVendor advisory
  42. 2026-08-03 10:36 UTCEPSS rescore
  43. 2026-08-03 01:14 UTCVendor advisory
  44. 2026-08-02 20:38 UTCVendor advisory
  45. 2026-08-02 16:53 UTCEG score recompute
  46. 2026-08-02 16:53 UTCVendor advisory
  47. 2026-08-02 02:26 UTCEPSS rescore
  48. 2026-08-01 04:16 UTCEPSS rescore
  49. 2026-07-30 16:27 UTCEPSS rescore
  50. 2026-07-30 12:26 UTCEG score recompute
  51. 2026-07-30 12:26 UTCVendor advisory
  52. 2026-07-30 12:09 UTCEG score recompute
  53. 2026-07-30 12:09 UTCVendor advisory
  54. 2026-07-30 01:30 UTCEPSS rescore
  55. 2026-07-28 15:36 UTCEPSS rescore
  56. 2026-07-26 14:54 UTCEPSS rescore
  57. 2026-07-26 14:54 UTCEPSS rescore
  58. 2026-07-25 14:18 UTCEPSS rescore
  59. 2026-07-25 14:17 UTCEPSS rescore
  60. 2026-07-24 14:17 UTCEPSS rescore
  61. 2026-07-23 14:18 UTCEPSS rescore
  62. 2026-07-23 14:18 UTCEPSS rescore
  63. 2026-07-23 03:08 UTCEG score recompute
  64. 2026-07-22 14:08 UTCEPSS rescore
  65. 2026-07-22 14:08 UTCEPSS rescore
  66. 2026-07-21 15:24 UTCEPSS rescore
  67. 2026-07-21 15:24 UTCEPSS rescore
  68. 2026-07-20 17:08 UTCEPSS rescore
  69. 2026-07-20 17:08 UTCEPSS rescore
  70. 2026-07-19 14:31 UTCEPSS rescore
  71. 2026-07-19 14:31 UTCEPSS rescore
  72. 2026-07-19 02:29 UTCEPSS rescore
  73. 2026-07-18 10:04 UTCEPSS rescore
  74. 2026-07-18 10:04 UTCEPSS rescore
  75. 2026-07-18 06:59 UTCOSV refresh

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-27962?
CVE-2026-27962 is a critical vulnerability published on March 16, 2026. Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a JWK Header Injection vulnerability in authlib's JWS implementation allows an unauthenticated attacker to forge arbitrary JWT tokens that pass signature verification. When key=None is passed to any…
When was CVE-2026-27962 disclosed?
CVE-2026-27962 was first published in the National Vulnerability Database on March 16, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-27962 actively exploited?
CVE-2026-27962 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 56.4% of all scored CVEs.
What is the CVSS score of CVE-2026-27962?
CVE-2026-27962 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-27962?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-27962, 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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