CVE-2025-59420

HIGHNVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.3% (16th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
Elevated
7.5EG
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: 0.3%CVSS: 7.5Exploit: 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 1.6.4, Authlib’s JWS verification accepts tokens that declare unknown critical header parameters (crit), violating RFC 7515 “must‑understand” semantics. An attacker can craft a signed token with a critical header (for example, bork or cnf) that strict verifiers reject but Authlib accepts. In mixed‑language fleets, this enables split‑brain verification and can lead to policy bypass, replay, or privilege escalation. This issue has been patched in version 1.6.4.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
65
EG Risk 65/100

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 (value × EchelonGraph’s weight)
Severity75% × 45%
The EG Score, 7.5 of 10.
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 or medium mission impact; Attend at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.3%
EPSS %ILE
16th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

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 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)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (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

September 22, 2025

Last Modified

November 3, 2025

References (3)

Vendor Advisories for CVE-2025-59420(10)

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

Patch Availability(11)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntupython3-authlib (1.3.0-1ubuntu0.1~esm1) @ noble2026-05-29ubuntu
redhatquay/quay-rhel8:17730976212026-03-10redhat
redhatquay/quay-rhel8:17701465652026-02-04redhat
redhatquay/quay-rhel8:v3.13.10-17657823912025-12-15redhat
redhatquay/quay-rhel8:3.12-17653615932025-12-10redhat
redhatquay/quay-rhel8:3.12-17653826022025-12-10redhat
redhatquay/quay-rhel8:3.9-17653827582025-12-10redhat
redhatquay/quay-rhel8:3.12-17653815022025-12-10redhat
redhatquay/quay-rhel8:3.10.17-17653841442025-12-10redhat
redhatquay/quay-rhel8:3.9-17642547562025-11-27redhat
redhatquay/quay-rhel8:3.10.17-17641684282025-11-26redhat

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
  • every version up to 0.15.4-1+deb11u1: fixed in 0.15.4-1+deb11u1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
python-authlib1.2.0-1
  • every version up to 1.2.0-1+deb12u1: fixed in 1.2.0-1+deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
python-authlib1.6.0-1
  • every version up to 1.6.0-1+deb13u1: fixed in 1.6.0-1+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
python-authlib1.6.0-1, 1.6.1-1, 1.6.3-1
  • every version up to 1.6.4-1: fixed in 1.6.4-1
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
authlib0.1 ... 1.6.3 (51 versions)
  • every version up to 1.6.4: fixed in 1.6.4
—

Weakness Classification(2)

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 11× in last 7d / 31× 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 it from the CNA feed. 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). Most recent first.

Showing the most recent 94 of 166 refreshes 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. 6 repeat rows among the latest 100 are merged into the row they repeat. The 72 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  2. 2026-10-14 16:31 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  3. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  4. 2026-10-12 16:53 UTCEG score recompute
  5. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  6. 2026-10-11 20:27 UTCEG score recompute
  7. 2026-10-11 18:39 UTCEG score recompute
  8. 2026-10-11 15:14 UTCEG score recompute
  9. 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  10. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  11. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  12. 2026-10-08 17:10 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  13. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  14. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  15. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  16. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  17. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  18. 2026-10-02 04:40 UTCOSV refresh
  19. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  20. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  21. 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  22. 2026-09-28 13:50 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  23. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  24. 2026-09-24 14:02 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  25. 2026-09-23 13:47 UTCEPSS rescoreEPSS 0.3% · 18th percentile
Show 69 more
  1. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  2. 2026-09-19 15:42 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  3. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  4. 2026-09-17 19:29 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  5. 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  6. 2026-09-16 05:14 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  7. 2026-09-13 16:46 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  8. 2026-09-12 23:06 UTCOSV refresh
  9. 2026-09-12 15:00 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  10. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  11. 2026-09-11 09:36 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  12. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  13. 2026-09-08 21:59 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  14. 2026-09-07 16:00 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  15. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  16. 2026-09-05 15:28 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  17. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  18. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  19. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  20. 2026-09-01 04:38 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  21. 2026-08-30 19:16 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  22. 2026-08-30 01:21 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  23. 2026-08-28 21:40 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  24. 2026-08-27 14:24 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  25. 2026-08-26 14:45 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  26. 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  27. 2026-08-25 03:26 UTCOSV refresh
  28. 2026-08-24 14:16 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  29. 2026-08-24 09:22 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  30. 2026-08-23 00:18 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  31. 2026-08-21 23:48 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  32. 2026-08-20 22:54 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  33. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  34. 2026-08-18 13:47 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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  36. 2026-08-16 14:55 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  37. 2026-08-16 02:13 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  38. 2026-08-15 01:29 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  39. 2026-08-13 21:59 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  40. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  41. 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  42. 2026-08-10 23:59 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  43. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  44. 2026-08-08 20:55 UTCOSV refresh
  45. 2026-08-08 16:36 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  46. 2026-08-07 16:26 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  47. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  48. 2026-08-05 19:16 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  49. 2026-08-04 15:09 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  50. 2026-08-04 10:37 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  51. 2026-08-03 10:35 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  52. 2026-08-02 02:26 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  53. 2026-08-01 04:15 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  54. 2026-07-30 16:27 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  55. 2026-07-30 01:30 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  56. 2026-07-28 15:35 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  57. 2026-07-26 14:54 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  58. 2026-07-25 14:17 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  59. 2026-07-24 14:17 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  60. 2026-07-23 19:41 UTCOSV refresh
  61. 2026-07-23 14:18 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  62. 2026-07-23 02:59 UTCEG score recompute
  63. 2026-07-22 14:07 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  64. 2026-07-21 15:24 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  65. 2026-07-20 17:08 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  66. 2026-07-19 02:28 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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  68. 2026-07-16 17:02 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  69. 2026-07-15 16:57 UTCEPSS rescoreEPSS 0.2% · 15th percentile

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Frequently asked(5)

What is CVE-2025-59420?
CVE-2025-59420 is a high-severity vulnerability; its CVE record was published on September 22, 2025. Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.4, Authlib’s JWS verification accepts tokens that declare unknown critical header parameters (crit), violating RFC 7515 “must‑understand” semantics. An attacker can craft a signed token with a critical…
When was the CVE record for CVE-2025-59420 published?
The CVE record for CVE-2025-59420 was published on September 22, 2025. 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 3, 2025; the record at its source may have been updated since.
Is CVE-2025-59420 actively exploited?
CVE-2025-59420 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (16th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2025-59420?
CVE-2025-59420 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2025-59420?
A fix for CVE-2025-59420 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2025-59420 are linked in the Vendor Advisories panel on this page.

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