PatchTheCVECVE-2026-110354: HAProxy 3 before 3.4.6 allows a remote unauthenticated attacker to cause a denial of service (persistent worke
CVE-2026-110354 is a high-severity flaw (CVSS 7.5) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
HAProxy 3 before 3.4.6 allows a remote unauthenticated attacker to cause a denial of service (persistent worker-thread CPU exhaustion) via an HTTP/1.1 chunked request. Although the H1 multiplexer drains the request before closing the stream, the parser repeatedly re-processes the same bytes without making progress. The affected thread stays busy at 100% CPU after timeouts expire and after the client disconnects, and repeated requests can consume
Why this priority
- High severity
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.8% (top 45%) |
| CISA exploited list | No |
| Weakness | CWE-835 |
| Published | 2026-10-22 |
| Last modified | 2026-10-22 |
Last updated 2026-10-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-110354?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-110354 being exploited?
CVE-2026-110354 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-110354 affect?
CVE-2026-110354 affects affected software. Severity is high (CVSS 7.5). HAProxy 3 before 3.4.6 allows a remote unauthenticated attacker to cause a denial of service (persistent worker-thread CPU exhaustion) via an HTTP/1.1 chunked request. Although the H1 multiplexer drains the request before closing the stream
How urgent is CVE-2026-110354?
Priority 45/100. High severity; Remotely exploitable, no login, no user action