Integer overflow in libevent - #VU136943
Published: July 6, 2026
Vulnerability identifier: #VU136943
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-190
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to integer truncation in evtag_unmarshal_header() and evtag_unmarshal_string() when parsing crafted wire-encoded length fields. A remote attacker can send specially crafted input with a length value above INT_MAX to cause a denial of service.
The issue is triggered when a wire uint32 length is converted to a signed int, causing negative or truncated values that lead to an oversized wrapped allocation request in downstream string unmarshalling.
Affected software
libevent
Remediation
Install security update from vendor's website.
libevent - update to 2.1.13