CVE-2026-63381

Advisory lineage Upstream: 0 Downstream: 1
Downstream
MGASA-2026-0294
Received
Published: 20 Aug 2026, 17:50
Last modified:20 Aug 2026, 17:50

Vulnerability Summary

Overall Risk (default)
low
23/100
CVSS Score
5.8 MEDIUM
v4.0 (cve.org)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

20 Aug 2026, 17:50
Published
Vulnerability first disclosed

Description

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a use-after-free in buffer.c when evbuffer_add_buffer_reference processes an output buffer whose out_total_len is zero. evbuffer_free_all_chains frees the initial empty chain without resetting outbuf->first, outbuf->last, or outbuf->last_with_datap, and APPEND_CHAIN_MULTICAST subsequently dereferences the dangling chain pointer. A caller that can drive this buffer state can cause memory corruption or a process crash. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

CVSS Metrics

  • v4.0•MEDIUM•Score: 5.8CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
  • v4.0•MEDIUM•Score: 5.8CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Techniques & Countermeasures

  • CWE-908•Use of Uninitialized Resource

    The product uses or accesses a resource that has not been initialized.

Affected Systems

  • libevent•libevent

    ≥ 2.2.0-alpha, < 2.2.2-alpha | < 2.1.13

References (5)