CVE-2026-63380

MEDIUMPre-NVD 5.75.7—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 98% of all CVEs by exploit prediction. 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
Elevated
5.7EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.7Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Libevent is an event notification library. Prior to 2.2.2-alpha, libevent can dereference invalid list pointers in ws.c when evws_new_session enters its error path after evhttp_start_ws_ succeeds but bufferevent_enable_locking_ fails. evws_connection_free sees a non-null http_server and unconditionally calls TAILQ_REMOVE even though the session was never inserted into http_server->ws_sessions. A local caller able to induce this allocation or locking failure can crash the process. This issue is fixed in version 2.2.2-alpha.

CVSS v3
5.7
EG Score
5.7(medium)
EG Risk
42(Track)
EG Risk 42/100SSVC: Track

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
Severity57% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

August 20, 2026

Last Modified

August 25, 2026

Advisory Details (3)

Auto-updated Aug 20, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_release.
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_commit Patch Available

commit 825c18bd99f5 (libevent/libevent)

Patch available: libevent/libevent release-2.2.2-alpha (contains commit 825c18bd99f5)

https://github.com/libevent/libevent/commit/825c18bd99f556b59d61200523237f264d5cc734
github Patch Available🟡 PoC Available

Null Pointer Dereference in `evws_new_session` · Advisory · libevent/libevent · GitHub

https://github.com/libevent/libevent/security/advisories/GHSA-3rpf-frgx-xq34

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 18× 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.

  1. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-29 18:16 UTCEG score recompute
  3. 2026-08-28 21:42 UTCEPSS rescore
  4. 2026-08-27 16:44 UTCEG score recompute
  5. 2026-08-27 14:25 UTCEPSS rescore
  6. 2026-08-26 16:34 UTCEG score recompute
  7. 2026-08-26 14:46 UTCEPSS rescore
  8. 2026-08-25 16:26 UTCEG score recompute
  9. 2026-08-25 15:31 UTCEG score recompute
  10. 2026-08-25 13:49 UTCEPSS rescore
  11. 2026-08-24 18:46 UTCEG score recompute
  12. 2026-08-23 18:38 UTCEG score recompute
  13. 2026-08-23 00:19 UTCEPSS rescore
  14. 2026-08-22 18:31 UTCEG score recompute
  15. 2026-08-21 23:49 UTCEPSS rescore
  16. 2026-08-20 18:17 UTCEG score recompute
  17. 2026-08-20 17:57 UTCEG score recompute
  18. 2026-08-20 17:56 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-63380?
CVE-2026-63380 is a medium vulnerability published on August 20, 2026. Libevent is an event notification library. Prior to 2.2.2-alpha, libevent can dereference invalid list pointers in ws.c when evwsnewsession enters its error path after evhttpstartws succeeds but buffereventenablelocking fails. evwsconnectionfree sees a non-null httpserver and unconditionally calls…
When was CVE-2026-63380 disclosed?
CVE-2026-63380 was first published in the National Vulnerability Database on August 20, 2026, with the most recent update on August 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63380 actively exploited?
CVE-2026-63380 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 98.4% of all scored CVEs.
What is the CVSS score of CVE-2026-63380?
CVE-2026-63380 has a CVSS v3 base score of 5.7 (NVD).
How do I remediate CVE-2026-63380?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63380, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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