CVE-2026-63385

CRITICALPre-NVD 9.29.2
EchelonGraph scoreMEDIUM confidence

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

This critical-severity CVE scores 9.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 1.3% (70th 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
Trending — Patch released this week

Also known asEUVD-2026-63563 (ENISA EUVD)Source: ENISA EUVD

9.2EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.3%CVSS: 9.2Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has two HTTP parsing weaknesses in http.c. evhttp_decode_uri_internal decodes percent-encoded %00 bytes into literal NUL characters, which can cause downstream C string operations to truncate a path and bypass validation performed on a different representation. evhttp_header_is_valid_value also accepts obsolete line folding in header values containing carriage return or line feed characters, allowing a proxy and libevent to interpret headers differently and enabling header injection or access control bypass. The CRLF header acceptance is fixed in versions 2.1.13 and 2.2.2-alpha, but the reviewed patches do not clearly remediate the URI NUL-truncation condition.

CVSS v3
9.2
EG Score
9.2CRITICALmedium confidence
EG Risk
42
EG Risk 42/100

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)
Severity92% × 45%
Impact severity (EG Severity): CVSS 9.2 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation1.3% × 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
1.3%
EPSS %ILE
70th
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 (9.2): severity, escalated by confirmed exploitation. This CVE's 9.2 is its impact severity (EG Severity), not escalated.

EG Severity
9.2 CRITICALCVSS-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
1.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). 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

August 20, 2026

Last Modified

October 26, 2026

Advisory Details (5)

Auto-updated Sep 15, 2026
Patch available. Sources: github_commit, github_release, github.
GitHub advisoryMentions a patch (unverified)

HTTP header handling bugs create risk of access control bypass. · Advisory · libevent/libevent · GitHub

https://github.com/libevent/libevent/security/advisories/GHSA-jcwh-pvf2-73p2
GitHub release Patch Available

Libevent 2.2.2-alpha

Patch available: libevent/libevent release-2.2.2-alpha

https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha
GitHub release Patch Available

Libevent 2.1.13-stable

Patch available: libevent/libevent release-2.1.13-stable

https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable
GitHub commit Patch Available

commit 9170dd35e647 (libevent/libevent)

Patch available: libevent/libevent release-2.1.13-stable (contains commit 9170dd35e647)

https://github.com/libevent/libevent/commit/9170dd35e64714613e8d13b290587cfc28e258e2
GitHub commit Patch Available

commit 758be0c0f69c (libevent/libevent)

Patch available: libevent/libevent release-2.2.2-alpha (contains commit 758be0c0f69c)

https://github.com/libevent/libevent/commit/758be0c0f69c1934ef9a84ab39e9f9e5fde2e6d0

Vendor Advisories for CVE-2026-63385(15)

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

Patch Availability(15)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibevent-pthreads-2.1-7 (2.1.12-stable-1ubuntu0.1) @ jammy2026-11-01ubuntu
redhatopenshift/ose-rhel-coreos-9:4.22.9.8.202610241758-02026-10-27redhat
redhatopenshift/ose-rhel-coreos-9:4.22.9.8.202609291947-02026-10-06redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17905899122026-09-28redhat
redhatcert-manager/cert-manager-operator-rhel9:17902724262026-09-28redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17902232792026-09-28redhat
redhatcert-manager/cert-manager-istio-csr-rhel9:17902237192026-09-28redhat
redhatcert-manager/cert-manager-operator-rhel9:17905898552026-09-28redhat
redhatcert-manager/cert-manager-istio-csr-rhel9:17905899142026-09-28redhat
redhatrhui5/rhua-rhel9:17902420042026-09-24redhat
redhatlibevent-main-2.1.13-1.hum12026-09-22redhat
redhatlibevent-0:2.1.8-11.el8_102026-09-16redhat
redhatlibevent-0:2.1.13-1.el9_82026-09-16redhat
redhatlibevent-0:2.1.13-1.el10_22026-09-16redhat
redhatlibevent-main-2.1.13-0.1.hum12026-09-03redhat

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

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
libevent2.1.12-stable-8
  • every version up to 2.1.12-stable-8+deb12u1: fixed in 2.1.12-stable-8+deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
libevent2.1.12-stable-10
  • every version up to 2.1.13-stable-1~deb13u1: fixed in 2.1.13-stable-1~deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
libevent2.1.12-stable-10, 2.1.13-stable-1~deb13u1
  • every version up to 2.1.13-stable-1: fixed in 2.1.13-stable-1
—

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 20× in last 7d / 106× 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 97 of 332 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. 3 repeat rows among the latest 100 are merged into the row they repeat. The 235 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 22:34 UTCEG score recompute
  2. 2026-11-01 22:34 UTCVendor advisory
  3. 2026-11-01 16:35 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  4. 2026-10-31 20:41 UTCEG score recompute
  5. 2026-10-31 20:41 UTCVendor advisory
  6. 2026-10-31 16:33 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  7. 2026-10-30 18:48 UTCEG score recompute
  8. 2026-10-30 18:48 UTCVendor advisory
  9. 2026-10-30 16:34 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  10. 2026-10-29 16:54 UTCEG score recompute
  11. 2026-10-29 16:54 UTCVendor advisory
  12. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  13. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  14. 2026-10-28 15:01 UTCEG score recompute
  15. 2026-10-28 15:01 UTCVendor advisory
  16. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  17. 2026-10-27 13:05 UTCVendor advisory
  18. 2026-10-27 12:18 UTCEG score recompute
  19. 2026-10-27 12:18 UTCVendor advisory
  20. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  21. 2026-10-26 10:26 UTCVendor advisory
  22. 2026-10-26 01:08 UTCEG score recompute
  23. 2026-10-26 01:08 UTCVendor advisory
  24. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  25. 2026-10-25 14:13 UTCEG score recompute
Show 72 more
  1. 2026-10-24 23:15 UTCEG score recompute
  2. 2026-10-24 23:15 UTCVendor advisory
  3. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  4. 2026-10-23 21:23 UTCEG score recompute
  5. 2026-10-23 21:23 UTCVendor advisory
  6. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  7. 2026-10-22 19:29 UTCEG score recompute
  8. 2026-10-22 19:29 UTCVendor advisory
  9. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  10. 2026-10-21 17:36 UTCEG score recompute
  11. 2026-10-21 17:36 UTCVendor advisory
  12. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  13. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  14. 2026-10-20 15:43 UTCEG score recompute
  15. 2026-10-20 15:43 UTCVendor advisory
  16. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  17. 2026-10-19 13:47 UTCEG score recompute
  18. 2026-10-19 13:47 UTCVendor advisory
  19. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  20. 2026-10-18 11:54 UTCVendor advisory
  21. 2026-10-18 03:23 UTCEG score recompute
  22. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  23. 2026-10-17 10:01 UTCEG score recompute
  24. 2026-10-17 10:01 UTCVendor advisory
  25. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  26. 2026-10-16 08:07 UTCEG score recompute
  27. 2026-10-16 08:07 UTCVendor advisory
  28. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  29. 2026-10-15 06:13 UTCEG score recompute
  30. 2026-10-15 06:13 UTCVendor advisory
  31. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  32. 2026-10-14 01:50 UTCEG score recompute
  33. 2026-10-14 01:50 UTCVendor advisory
  34. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  35. 2026-10-12 22:02 UTCEG score recompute
  36. 2026-10-12 22:02 UTCVendor advisory
  37. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  38. 2026-10-12 15:49 UTCEG score recompute
  39. 2026-10-12 06:13 UTCVendor advisory
  40. 2026-10-11 19:33 UTCEG score recompute
  41. 2026-10-11 16:48 UTCEG score recompute
  42. 2026-10-11 14:10 UTCEG score recompute
  43. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  44. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  45. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  46. 2026-10-09 08:27 UTCEG score recompute
  47. 2026-10-09 08:27 UTCVendor advisory
  48. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  49. 2026-10-08 09:12 UTCVendor advisory
  50. 2026-10-08 05:19 UTCEG score recompute
  51. 2026-10-08 05:19 UTCVendor advisory
  52. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  53. 2026-10-07 10:06 UTCVendor advisory
  54. 2026-10-07 05:16 UTCVendor advisory
  55. 2026-10-07 01:16 UTCVendor advisory
  56. 2026-10-06 21:19 UTCVendor advisory
  57. 2026-10-06 16:53 UTCEG score recompute
  58. 2026-10-06 16:53 UTCVendor advisory
  59. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  60. 2026-10-06 12:20 UTCVendor advisory
  61. 2026-10-06 07:52 UTCVendor advisory
  62. 2026-10-06 03:24 UTCVendor advisory
  63. 2026-10-06 03:24 UTCVendor advisory
  64. 2026-10-05 17:44 UTCEG score recompute
  65. 2026-10-05 17:44 UTCVendor advisory
  66. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  67. 2026-10-05 13:52 UTCVendor advisory
  68. 2026-10-05 09:29 UTCVendor advisory
  69. 2026-10-05 05:28 UTCVendor advisory
  70. 2026-10-05 01:35 UTCEG score recompute
  71. 2026-10-05 01:35 UTCVendor advisory
  72. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 44th percentile

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Frequently asked(5)

What is CVE-2026-63385?
CVE-2026-63385 is a critical-severity vulnerability; its CVE record was published on August 20, 2026. Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has two HTTP parsing weaknesses in http.c. evhttp_decode_uri_internal decodes percent-encoded %00 bytes into literal NUL characters, which can cause downstream C string operations to truncate a path and bypass…
When was the CVE record for CVE-2026-63385 published?
The CVE record for CVE-2026-63385 was published on August 20, 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 October 26, 2026; the record at its source may have been updated since.
Is CVE-2026-63385 actively exploited?
CVE-2026-63385 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.3% probability of exploitation in the next 30 days (70th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-63385?
CVE-2026-63385 has a CVSS base score of 9.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-63385?
A fix for CVE-2026-63385 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-63385 are linked in the Vendor Advisories panel on this page.

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