CVE-2026-110353 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.
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-110353?
CVE-2026-110353 is a high-severity vulnerability in HAProxy, published on 22 Oct 2026.
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.
Weakness: CWE-252
Which versions are affected by CVE-2026-110353?
How do I fix CVE-2026-110353?
Upgrade to a fixed version.
Is CVE-2026-110353 being exploited?
There is no known exploitation of CVE-2026-110353 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-110353, GHSA-p9cc-qc4f-7x35, UBUNTU-CVE-2026-110353.