CVE-2026-103399
Libsoup: soupserver: http/1 request smuggling via undrained expect: 100-continue body
- State
- Published
- Severity
- 5.3 Medium
- Published
- Sep 30, 2026
- Updated
- Sep 30, 2026
- Reserved
- Sep 30, 2026
Description
A flaw was found in SoupServer (libsoup). When an HTTP/1.x client sends a request with Expect: 100-continue and a request body, and SoupServer returns an early final (non-1xx) response before the body is read, the server neither drains the declared body bytes nor closes the connection. On a keep-alive connection, those leftover bytes are interpreted as a subsequent HTTP request. A remote, unauthenticated attacker can place a complete HTTP request in the body and cause SoupServer to process that smuggled request, leading to unintended request handling.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.3 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N | redhat |
Weaknesses
- CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Affected Products
| Product | Versions |
|---|---|
Red Hat Enterprise Linux 10Red Hat | |
Red Hat Enterprise Linux 6Red Hat | |
Red Hat Enterprise Linux 7Red Hat | |
Red Hat Enterprise Linux 8Red Hat | |
Red Hat Enterprise Linux 9Red Hat |
References
- https://access.redhat.com/security/cve/CVE-2026-103399vdb-entry
- RHBZ#2543949issue-tracking
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.