CVE-2026-27962

CRITICALPre-NVD 9.19.1
EchelonGraph scoreMEDIUM confidence

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

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-03-16. A secondary CVSS source baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Elevated

Also known asEUVD-2026-12478 (ENISA EUVD) · GHSA-wvwj-cvrp-7pv5 (GitHub Security Advisories) · PYSEC-2026-287 (OSV.dev)Source: ENISA EUVD

9.1EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 9.1Exploit: No code on recordExposed services: Not assessed

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
9.1CRITICALmedium confidence
EG Risk
72
EG Risk 72/100

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)
Severity91% × 45%
Impact severity (EG Severity): CVSS 9.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.6%
EPSS %ILE
49th
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 (9.1): severity, escalated by confirmed exploitation. This CVE's 9.1 is its impact severity (EG Severity), not escalated.

EG Severity
9.1 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.6% 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 low, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days 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 low, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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)3 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (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

March 16, 2026

Last Modified

September 10, 2026

Advisory Details (11)

Auto-updated Sep 15, 2026
Patch available. Sources: github_commit, github_release, github, redhat.
Red Hat

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
Red HatMentions a patch (unverified)

CVE-2026-27962 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-27962
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:7314
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:5665
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:48085
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:24853
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:19375
GitHub advisoryMentions a patch (unverified)

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

Patch Availability(7)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntupython3-authlib (1.6.7-1ubuntu0.1~esm1) @ resolute2026-11-11ubuntu
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
pipauthlib @ 1.6.9 (fixes <= 1.6.8)—ghsa

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 rangeFix by version rangeDependents
python-authlib0.15.4-1, 0.15.4-1+deb11u1
  • every version up to 0.15.4-1+deb11u2: fixed in 0.15.4-1+deb11u2
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
python-authlib1.2.0-1, 1.2.0-1+deb12u1
  • every version up to 1.2.0-1+deb12u2: fixed in 1.2.0-1+deb12u2
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
python-authlib1.6.0-1 ... 1.7.2-2 (13 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
python-authlib1.6.0-1 ... 1.6.8-1 (8 versions)
  • every version up to 1.6.9-1: fixed in 1.6.9-1
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
authlib0.1 ... 1.6.8 (56 versions)
  • every version up to 1.6.9: fixed in 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 21× in last 7d / 77× 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.

Showing the most recent 100 of 297 rows on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 197 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-12 20:55 UTCEchelonGraph re-scored
  2. 2026-11-12 20:55 UTCVendor advisory
  3. 2026-11-12 20:55 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  4. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  5. 2026-11-11 23:11 UTCEchelonGraph re-scored
  6. 2026-11-11 23:11 UTCVendor advisory
  7. 2026-11-11 23:11 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  8. 2026-11-11 16:39 UTCEPSS rescoreEPSS 0.6% · 49th percentile
  9. 2026-11-11 01:27 UTCEchelonGraph re-scored
  10. 2026-11-11 01:27 UTCVendor advisory
  11. 2026-11-11 01:27 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  12. 2026-11-10 16:43 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  13. 2026-11-10 03:43 UTCEchelonGraph re-scored
  14. 2026-11-10 03:43 UTCVendor advisory
  15. 2026-11-10 03:43 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  16. 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  17. 2026-11-09 05:59 UTCEchelonGraph re-scored
  18. 2026-11-09 05:59 UTCVendor advisory
  19. 2026-11-09 05:59 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  20. 2026-11-08 16:39 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  21. 2026-11-08 08:16 UTCEchelonGraph re-scored
  22. 2026-11-08 08:16 UTCVendor advisory
  23. 2026-11-08 08:16 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  24. 2026-11-07 16:38 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  25. 2026-11-07 10:32 UTCEchelonGraph re-scored
Show 75 more
  1. 2026-11-07 10:32 UTCVendor advisory
  2. 2026-11-07 10:32 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  3. 2026-11-06 16:37 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  4. 2026-11-06 12:49 UTCEchelonGraph re-scored
  5. 2026-11-06 12:49 UTCVendor advisory
  6. 2026-11-06 12:49 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  7. 2026-11-06 04:55 UTCOSV refresh
  8. 2026-11-05 16:37 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  9. 2026-11-05 15:06 UTCVendor advisory
  10. 2026-11-05 15:06 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  11. 2026-11-04 17:22 UTCEchelonGraph re-scored
  12. 2026-11-04 17:22 UTCVendor advisory
  13. 2026-11-04 17:22 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  14. 2026-11-04 16:35 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  15. 2026-11-03 19:38 UTCEchelonGraph re-scored
  16. 2026-11-03 19:38 UTCVendor advisory
  17. 2026-11-03 19:38 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  18. 2026-11-03 16:47 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  19. 2026-11-02 21:55 UTCEchelonGraph re-scored
  20. 2026-11-02 21:55 UTCVendor advisory
  21. 2026-11-02 21:55 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  22. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  23. 2026-11-02 00:11 UTCEchelonGraph re-scored
  24. 2026-11-02 00:11 UTCVendor advisory
  25. 2026-11-02 00:11 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  26. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  27. 2026-11-01 07:55 UTCGHSA enrichmentGHSA-wvwj-cvrp-7pv5 · GitHub severity CRITICAL · GitHub CVSS 9.1
  28. 2026-11-01 07:55 UTCEchelonGraph re-scored
  29. 2026-11-01 02:27 UTCEchelonGraph re-scored
  30. 2026-11-01 02:27 UTCVendor advisory
  31. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  32. 2026-10-31 04:43 UTCEchelonGraph re-scored
  33. 2026-10-31 04:43 UTCVendor advisory
  34. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  35. 2026-10-30 07:00 UTCEchelonGraph re-scored
  36. 2026-10-30 07:00 UTCVendor advisory
  37. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  38. 2026-10-29 09:17 UTCEchelonGraph re-scored
  39. 2026-10-29 09:17 UTCVendor advisory
  40. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  41. 2026-10-28 11:33 UTCEchelonGraph re-scored
  42. 2026-10-28 11:33 UTCVendor advisory
  43. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  44. 2026-10-27 13:29 UTCEchelonGraph re-scored
  45. 2026-10-27 13:29 UTCVendor advisory
  46. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  47. 2026-10-26 15:17 UTCVendor advisory
  48. 2026-10-25 16:34 UTCEchelonGraph re-scored
  49. 2026-10-25 16:34 UTCVendor advisory
  50. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  51. 2026-10-25 14:38 UTCEchelonGraph re-scored
  52. 2026-10-24 18:47 UTCEchelonGraph re-scored
  53. 2026-10-24 18:47 UTCVendor advisory
  54. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  55. 2026-10-23 21:04 UTCEchelonGraph re-scored
  56. 2026-10-23 21:04 UTCVendor advisory
  57. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  58. 2026-10-22 23:21 UTCEchelonGraph re-scored
  59. 2026-10-22 23:21 UTCVendor advisory
  60. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  61. 2026-10-22 01:35 UTCEchelonGraph re-scored
  62. 2026-10-22 01:35 UTCVendor advisory
  63. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  64. 2026-10-21 03:52 UTCEchelonGraph re-scored
  65. 2026-10-21 03:52 UTCVendor advisory
  66. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  67. 2026-10-20 06:00 UTCEchelonGraph re-scored
  68. 2026-10-20 06:00 UTCVendor advisory
  69. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  70. 2026-10-19 07:55 UTCEchelonGraph re-scored
  71. 2026-10-19 07:55 UTCVendor advisory
  72. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  73. 2026-10-18 09:47 UTCVendor advisory
  74. 2026-10-18 03:50 UTCEchelonGraph re-scored
  75. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile

Frequently asked(5)

What is CVE-2026-27962?
CVE-2026-27962 is a critical-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-27962 published?
The CVE record for CVE-2026-27962 was published on March 16, 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 September 10, 2026; the record at its source may have been updated since.
Is CVE-2026-27962 actively exploited?
CVE-2026-27962 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (49th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-27962?
CVE-2026-27962 has a CVSS base score of 9.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-27962?
A fix for CVE-2026-27962 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-27962 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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