CVE-2026-103399: Red Hat Enterprise Linux 10

Medium severity, CVSS 5.3. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Red Hat Red Hat Enterprise Linux 10
• Red Hat Red Hat Enterprise Linux 6
• Red Hat Red Hat Enterprise Linux 7
• Red Hat Red Hat Enterprise Linux 8
• Red Hat Red Hat Enterprise Linux 9

Published 2026-09-30. Last modified 2026-09-30.