CVE-2026-103399
Publication date 30 September 2026
Last updated 3 November 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| libsoup2.4 | 26.10 stonking |
Needs evaluation
|
| 26.04 LTS resolute |
Fixed in 2.74.3-10.1ubuntu5+esm4
|
|
| 24.04 LTS noble |
Fixed in 2.74.3-6ubuntu1.10
|
|
| 22.04 LTS jammy |
Fixed in 2.74.2-3ubuntu0.10
|
|
| 20.04 LTS focal |
Fixed in 2.70.0-1ubuntu0.5+esm5
|
|
| 18.04 LTS bionic |
Fixed in 2.62.1-1ubuntu0.4+esm10
|
|
| 16.04 LTS xenial |
Fixed in 2.52.2-1ubuntu0.3+esm9
|
|
| libsoup3 | 26.10 stonking |
Fixed in 3.6.6-1ubuntu3.1
|
| 26.04 LTS resolute |
Fixed in 3.6.6-1ubuntu0.2
|
|
| 24.04 LTS noble |
Fixed in 3.4.4-5ubuntu0.10
|
|
| 22.04 LTS jammy |
Fixed in 3.0.7-0ubuntu1+esm10
|
Get expanded security coverage with Ubuntu Pro
Reduce your average CVE exposure time from 98 days to 1 day with expanded CVE patching, ten-years security maintenance and optional support for the full stack of open-source applications. Free for personal use.
Get Ubuntu Pro 30-day free trialSeverity score breakdown
CVSS version: CVSS v3.0
Base score
5.3 · Medium
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
References
Related Ubuntu Security Notices (USN)
- USN-8975-1
- libsoup vulnerabilities
- 3 November 2026