What’s Vulnerable › Vulnerabilities
CVE-2026-110353
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.7% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-10-22 · updated 2026-10-22
- Weakness: CWE-252
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 products
- HAProxy: from 3.2.0 before 3.2.26; from 3.3.0 before 3.3.17; from 3.4.0 before 3.4.6; from 3.5-dev before 3.5-dev9 — fixed in 3.2.26, 3.3.17, 3.4.6, 3.5-dev9
- HAProxy Enterprise Edition: from 3.2.0r1 before 3.2r1-378.1259; from 3.3.0r1 before 3.3r1-377.1005 — fixed in 3.2r1-378.1259, 3.3r1-377.1005
- HAProxy Kubernetes Ingress Controller: from 3.2.0 before 3.2.17 — fixed in 3.2.17
- Haproxy Kubernetes Ingress Controller Enterprise: from 3.2.0 before 3.2.17-ee1; from 3.0 before 3.0.16-ee17; from 1.11 before 1.11.14-ee11 — fixed in 1.11.14-ee11, 3.0.16-ee17, 3.2.17-ee1
How to fix
Upgrade to a fixed version: HAProxy 3.2.26, 3.3.17, 3.4.6, 3.5-dev9; HAProxy Enterprise Edition 3.2r1-378.1259, 3.3r1-377.1005; HAProxy Kubernetes Ingress Controller 3.2.17; Haproxy Kubernetes Ingress Controller Enterprise 1.11.14-ee11, 3.0.16-ee17, 3.2.17-ee1. Check the vendor advisory for mitigations.
References
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