USN-8957-1: authd vulnerability
USN-8957-1
Summary
Alexis Challande discovered that libevent incorrectly handled certain empty output buffers. An attacker could possibly use this issue to trigger a use-after-free, resulting in a denial of service or arbitrary code execution. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-63381) Rajat Raghav discovered that libevent incorrectly handled certain HTTP requests.
An attacker could possibly use this issue to desynchronize HTTP request boundaries, resulting in HTTP request smuggling. (CVE-2026-63382) Qiu Sihao discovered that libevent incorrectly handled certain malformed tagged RPC data. An attacker could possibly use this issue to trigger an out-of-bounds read, resulting in a denial of service. (CVE-2026-63383) Qiu Sihao discovered that libevent incorrectly handled certain large payload lengths in tagged RPC data.
An attacker could possibly use this issue to consume excessive system resources, resulting in a denial of service. (CVE-2026-63384) Asaf Meizner discovered that libevent incorrectly handled certain HTTP URIs and header values. An attacker could possibly use this issue to cause HTTP messages to be interpreted inconsistently, resulting in security restrictions being bypassed. (CVE-2026-63385)
Products covered
A separate affected-products list was not included in the collected bulletin.
Remediation
Separate remediation guidance was not included in the collected bulletin.
CVEs in this advisory 5
Updates
- Published by Ubuntu
The publication date reported by the vendor.
- Added to SecurityAlert
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- Confirmed at the source
Our collector saw this advisory during a later source check.