An issue was discovered in HAProxy before 3.3.6. The HTTP/3 parser does not check that the received body length matches a previously announced content-length when the stream is closed via a frame with an empty payload. This can cause desynchronization issues with the backend server and could be used for request smuggling. The earliest affected version is 2.6.
CVSS Details
- CVSS 3.1 Base Score: 5.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | Upgrade haproxy | Jul 23, 2026 | Jul 23, 2026 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Apr 13, 2026 |
| Ubuntu | — | Upgrade haproxy | Apr 28, 2026 | Apr 27, 2026 |
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