Integer underflow in Apache Traffic Server - CVE-2026-111808
Published: October 23, 2026
Vulnerability identifier: #VU157327
CSH Severity: High
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: CVE-2026-111808
CWE-ID: CWE-191
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service by exhausting an HTTP/1.1 origin's worker pool.
The vulnerability exists due to an integer underflow in Apache Traffic Server's HTTP/2 DATA frame padding handling when processing a malformed padded frame. A remote attacker can send a specially crafted padded HTTP/2 DATA frame to exhaust the backend HTTP/1.1 worker pool and cause a denial of service.
Affected software
Apache Traffic Server
How to mitigate CVE-2026-111808
Install security update from vendor's website.
Apache Traffic Server - addressed in versions 9.2.16, 10.1.5, 10.2.1