Vulnerability · Published Oct 22, 2026 · Assigned by mitre
CVE-2026-110353
High 7.5
In plain English
A high-severity security flaw in HAProxy from HAProxy. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 55% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
HAProxy 3.2 before 3.4.6 allows a remote unauthenticated attacker to cause a denial of service (worker-thread CPU exhaustion) via a truncated HTTP/2 PING frame. h2c_handle_ping in src/mux_h2.c does not check for a short read, unlike the other H2 frame handlers. Because the incomplete frame cannot be processed, its data is never consumed, and the H2 multiplexer tasklet is repeatedly woken by that pending data without making progress. The CPU spins until timeout http-request closes the connection, and an attacker opening many such connections can sustain high CPU usage.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | haproxy | no fix listed | DEBIAN-CVE-2026-110353 |
| Debian:13 | haproxy | no fix listed | DEBIAN-CVE-2026-110353 |
| Debian:14 | haproxy | 3.2.26-1 | DEBIAN-CVE-2026-110353 |
| Ubuntu:22.04:LTS | haproxy | 2.4.30-0ubuntu0.22.04.3 | USN-8972-1 |
| Ubuntu:22.04:LTS | haproxy | 2.4.30-0ubuntu0.22.04.3 | UBUNTU-CVE-2026-110353 |
| Ubuntu:24.04:LTS | haproxy | 2.8.30-0ubuntu0.24.04.2 | USN-8972-1 |
| Ubuntu:24.04:LTS | haproxy | 2.8.30-0ubuntu0.24.04.2 | UBUNTU-CVE-2026-110353 |
| Ubuntu:26.04:LTS | haproxy | 3.2.25-0ubuntu0.26.04.2 | UBUNTU-CVE-2026-110353 |
| Ubuntu:26.04:LTS | haproxy | 3.2.25-0ubuntu0.26.04.2 | USN-8972-1 |
| Ubuntu:26.10 | haproxy | 3.4.2-1ubuntu4.1 | USN-8972-1 |
| Ubuntu:26.10 | haproxy | 3.4.2-1ubuntu4.1 | UBUNTU-CVE-2026-110353 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| HAProxy | HAProxy | 3.2.0 – before 3.2.263.3.0 – before 3.3.173.4.0 – before 3.4.63.5-dev – before 3.5-dev9 |
| HAProxy | HAProxy Enterprise Edition | 3.2.0r1 – before 3.2r1-378.12593.3.0r1 – before 3.3r1-377.1005 |
| HAProxy | Kubernetes Ingress Controller | 3.2.0 – before 3.2.17 |
| Haproxy | Kubernetes Ingress Controller Enterprise | 3.2.0 – before 3.2.17-ee13.0 – before 3.0.16-ee171.11 – before 1.11.14-ee11 |
Weakness: CWE-252 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H