CVE-2026-63382

CRITICALPre-NVD 9.29.2—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.8% (54th percentile of EPSS-scored CVEs). 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
9.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 9.2Exploit: Elevated riskExposed 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, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

CVSS v3
9.2
EG Score
9.2CRITICALmedium confidence
EG Risk
72
EG Risk 72/100CISA SSVC

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
Severity92% × 45%
Exploitation40% × 40%
Automatability100% × 15%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
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
0.8%
EPSS %ILE
54th
KEV
Not listed

CISA SSVCTrack 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). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 20, 2026

Last Modified

September 9, 2026

Advisory Details (7)

Auto-updated Sep 15, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
githubMentions a patch (unverified)🟡 PoC Available

libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling · Advisory · libevent/libevent · GitHub

https://github.com/libevent/libevent/security/advisories/GHSA-q39v-w2g7-gr8j
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 ac38703b2d31 (libevent/libevent)

Patch available: libevent/libevent release-2.1.13-stable (contains commit ac38703b2d31)

https://github.com/libevent/libevent/commit/ac38703b2d312200c4f967f02936af0118d384a0
github_commit Patch Available

commit 83ba67373032 (libevent/libevent)

Patch available: libevent/libevent release-2.2.2-alpha (contains commit 83ba67373032)

https://github.com/libevent/libevent/commit/83ba67373032334559b82409db035dd8c3cc1660
github_commit Patch Available

commit 5119ceb00557 (libevent/libevent)

Patch available: libevent/libevent release-2.2.2-alpha (contains commit 5119ceb00557)

https://github.com/libevent/libevent/commit/5119ceb00557bf007f9065709e852686f3c0bb6e
github_commit Patch Available

commit 10abb34b8dc3 (libevent/libevent)

Patch available: libevent/libevent release-2.1.13-stable (contains commit 10abb34b8dc3)

https://github.com/libevent/libevent/commit/10abb34b8dc3e1184de315dd261ce4b77563cda6

Vendor Advisories for CVE-2026-63382(11)

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

Patch Availability(12)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibevent-pthreads-2.0-5 (2.0.21-stable-2ubuntu0.16.04.1+esm1) @ xenial2026-10-08ubuntu
redhatcert-manager/jetstack-cert-manager-rhel9:17905899122026-09-28redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17902232792026-09-28redhat
redhatcert-manager/cert-manager-istio-csr-rhel9:17902237192026-09-28redhat
redhatcert-manager/cert-manager-operator-rhel9:17902724262026-09-28redhat
redhatcert-manager/cert-manager-istio-csr-rhel9:17905899142026-09-28redhat
redhatcert-manager/cert-manager-operator-rhel9:17905898552026-09-28redhat
redhatrhui5/rhua-rhel9:17902420042026-09-24redhat
redhatlibevent-0:2.1.13-1.el10_22026-09-16redhat
redhatlibevent-0:2.1.8-11.el8_102026-09-16redhat
redhatlibevent-0:2.1.13-1.el9_82026-09-16redhat
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 34× in last 7d / 187× 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 267 total refreshes for this CVE.

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

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-63382?
CVE-2026-63382 is a critical vulnerability published on August 20, 2026. Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttpfindheader can select only the first…
When was CVE-2026-63382 disclosed?
CVE-2026-63382 was first published on August 20, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63382 actively exploited?
CVE-2026-63382 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (54th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-63382?
CVE-2026-63382 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-2026-63382?
A fix for CVE-2026-63382 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-63382 are linked in the Vendor Advisories panel on this page.

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