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

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
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
EG Likelihood
1.3% 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 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

Patch Availability(15)

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 13× in last 7d / 60× 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 → 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 368 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 268 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:53 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  2. 2026-11-12 17:32 UTCEchelonGraph re-scored
  3. 2026-11-12 17:32 UTCVendor advisory
  4. 2026-11-12 16:34 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  5. 2026-11-11 16:40 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  6. 2026-11-11 15:39 UTCEchelonGraph re-scored
  7. 2026-11-11 15:39 UTCVendor advisory
  8. 2026-11-10 16:45 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  9. 2026-11-10 13:46 UTCEchelonGraph re-scored
  10. 2026-11-10 13:46 UTCVendor advisory
  11. 2026-11-09 16:35 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  12. 2026-11-09 11:53 UTCEchelonGraph re-scored
  13. 2026-11-09 11:53 UTCVendor advisory
  14. 2026-11-08 16:40 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  15. 2026-11-08 09:59 UTCEchelonGraph re-scored
  16. 2026-11-08 09:59 UTCVendor advisory
  17. 2026-11-07 16:39 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  18. 2026-11-07 08:06 UTCEchelonGraph re-scored
  19. 2026-11-07 08:06 UTCVendor advisory
  20. 2026-11-06 16:39 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  21. 2026-11-06 14:55 UTCOSV refresh
  22. 2026-11-06 06:12 UTCEchelonGraph re-scored
  23. 2026-11-06 06:12 UTCVendor advisory
  24. 2026-11-05 16:38 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  25. 2026-11-05 04:19 UTCEchelonGraph re-scored
Show 75 more
  1. 2026-11-05 04:19 UTCVendor advisory
  2. 2026-11-04 16:36 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  3. 2026-11-04 02:20 UTCEchelonGraph re-scored
  4. 2026-11-04 02:20 UTCVendor advisory
  5. 2026-11-03 16:48 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  6. 2026-11-03 00:27 UTCEchelonGraph re-scored
  7. 2026-11-03 00:27 UTCVendor advisory
  8. 2026-11-02 16:45 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  9. 2026-11-01 22:34 UTCEchelonGraph re-scored
  10. 2026-11-01 22:34 UTCVendor advisory
  11. 2026-11-01 16:35 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  12. 2026-10-31 20:41 UTCEchelonGraph re-scored
  13. 2026-10-31 20:41 UTCVendor advisory
  14. 2026-10-31 16:33 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  15. 2026-10-30 18:48 UTCEchelonGraph re-scored
  16. 2026-10-30 18:48 UTCVendor advisory
  17. 2026-10-30 16:34 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  18. 2026-10-29 16:54 UTCEchelonGraph re-scored
  19. 2026-10-29 16:54 UTCVendor advisory
  20. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  21. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  22. 2026-10-28 15:01 UTCEchelonGraph re-scored
  23. 2026-10-28 15:01 UTCVendor advisory
  24. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  25. 2026-10-27 13:05 UTCVendor advisory
  26. 2026-10-27 12:18 UTCEchelonGraph re-scored
  27. 2026-10-27 12:18 UTCVendor advisory
  28. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  29. 2026-10-26 10:26 UTCVendor advisory
  30. 2026-10-26 01:08 UTCEchelonGraph re-scored
  31. 2026-10-26 01:08 UTCVendor advisory
  32. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  33. 2026-10-25 14:13 UTCEchelonGraph re-scored
  34. 2026-10-24 23:15 UTCEchelonGraph re-scored
  35. 2026-10-24 23:15 UTCVendor advisory
  36. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  37. 2026-10-23 21:23 UTCEchelonGraph re-scored
  38. 2026-10-23 21:23 UTCVendor advisory
  39. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  40. 2026-10-22 19:29 UTCEchelonGraph re-scored
  41. 2026-10-22 19:29 UTCVendor advisory
  42. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  43. 2026-10-21 17:36 UTCEchelonGraph re-scored
  44. 2026-10-21 17:36 UTCVendor advisory
  45. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  46. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  47. 2026-10-20 15:43 UTCEchelonGraph re-scored
  48. 2026-10-20 15:43 UTCVendor advisory
  49. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  50. 2026-10-19 13:47 UTCEchelonGraph re-scored
  51. 2026-10-19 13:47 UTCVendor advisory
  52. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  53. 2026-10-18 11:54 UTCVendor advisory
  54. 2026-10-18 03:23 UTCEchelonGraph re-scored
  55. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  56. 2026-10-17 10:01 UTCEchelonGraph re-scored
  57. 2026-10-17 10:01 UTCVendor advisory
  58. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  59. 2026-10-16 08:07 UTCEchelonGraph re-scored
  60. 2026-10-16 08:07 UTCVendor advisory
  61. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  62. 2026-10-15 06:13 UTCEchelonGraph re-scored
  63. 2026-10-15 06:13 UTCVendor advisory
  64. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  65. 2026-10-14 01:50 UTCEchelonGraph re-scored
  66. 2026-10-14 01:50 UTCVendor advisory
  67. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  68. 2026-10-12 22:02 UTCEchelonGraph re-scored
  69. 2026-10-12 22:02 UTCVendor advisory
  70. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  71. 2026-10-12 15:49 UTCEchelonGraph re-scored
  72. 2026-10-12 06:13 UTCVendor advisory
  73. 2026-10-11 19:33 UTCEchelonGraph re-scored
  74. 2026-10-11 16:48 UTCEchelonGraph re-scored
  75. 2026-10-11 14:10 UTCEchelonGraph re-scored

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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