CVE-2026-110354
HAProxy 3 before 3.4.6 allows a remote unauthenticated attacker to cause a denial of service…
- Risk score
- 61/100
- CVSS
- 7.5 v3.1
- Exploit chance (30 days)
- 0.8%
- Published
- 22 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- 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. Th…
- Affected
- See advisory
- Fix
- Upgrade the product to 3.4.6 or later.
- Exploitation
- No known exploitation
Why it is Amber
- CVSS 7.5 high
- Remotely exploitable without logging in
References
Original description
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 all worker threads until the process is restarted.
Last activity 22 Oct 2026. Patch Forecast updates every hour.