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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| 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 | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 13 | libsoup3 +1 | No fix yet | — |
| Debian 12 | libsoup3 +1 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | libsoup2.4 | No fix yet | — |
| Ubuntu 26.10 | libsoup3 | 3.6.6-1ubuntu3.1 | USN-8975-1 |
| Ubuntu 26.04 LTS | libsoup3 | 3.6.6-1ubuntu0.2 | USN-8975-1 |
| Ubuntu 24.04 LTS | libsoup2.4 | 2.74.3-6ubuntu1.10 | USN-8975-1 |
| Ubuntu 24.04 LTS | libsoup3 | 3.4.4-5ubuntu0.10 | USN-8975-1 |
| Ubuntu 22.04 LTS | libsoup2.4 | 2.74.2-3ubuntu0.10 | USN-8975-1 |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | libsoup2.4 | 2.74.3-10.1ubuntu5+esm4 | USN-8975-1 |
| Ubuntu Pro 22.04 LTS | libsoup3 | 3.0.7-0ubuntu1+esm10 | USN-8975-1 |
| Ubuntu Pro 20.04 LTS | libsoup2.4 | 2.70.0-1ubuntu0.5+esm5 | USN-8975-1 |
| Ubuntu Pro 18.04 LTS | libsoup2.4 | 2.62.1-1ubuntu0.4+esm10 | USN-8975-1 |
| Ubuntu Pro 16.04 LTS | libsoup2.4 | 2.52.2-1ubuntu0.3+esm9 | USN-8975-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | libsoup | 3.4.4-150600.3.62.1 | SUSE-SU-2026:5062-1 |
| SLES 15 SP7 | libsoup2 | 2.74.3-150600.4.42.1 | SUSE-SU-2026:4703-1 |
| SLES 15 SP6 | libsoup | 3.4.4-150600.3.62.1 | SUSE-SU-2026:5062-1 |
| SLES 15 SP6 | libsoup2 | 2.74.3-150600.4.42.1 | SUSE-SU-2026:4703-1 |
| SLES 15 SP5 | libsoup | 3.0.4-150400.3.58.1 | SUSE-SU-2026:5063-1 |
| SLES 15 SP5 | libsoup2 | 2.74.3-150400.3.43.1 | SUSE-SU-2026:4739-1 |
| SLES 15 SP4 | libsoup | 3.0.4-150400.3.58.1 | SUSE-SU-2026:5063-1 |
| SLES 15 SP4 | libsoup2 | 2.74.3-150400.3.43.1 | SUSE-SU-2026:4739-1 |
| SLES 12 SP5 | libsoup | 2.62.2-5.49.1 | SUSE-SU-2026:4690-1 |
Show 11 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | libsoup | 3.6.6-160000.5.1 | SUSE-SU-2026:24470-1 |
| SLES for SAP 15 SP6 | libsoup | 3.4.4-150600.3.62.1 | SUSE-SU-2026:5062-1 |
| SLES for SAP 15 SP6 | libsoup2 | 2.74.3-150600.4.42.1 | SUSE-SU-2026:4703-1 |
| SLES for SAP 15 SP5 | libsoup | 3.0.4-150400.3.58.1 | SUSE-SU-2026:5063-1 |
| SLES for SAP 15 SP5 | libsoup2 | 2.74.3-150400.3.43.1 | SUSE-SU-2026:4739-1 |
| SLES for SAP 15 SP4 | libsoup | 3.0.4-150400.3.58.1 | SUSE-SU-2026:5063-1 |
| SLES for SAP 15 SP4 | libsoup2 | 2.74.3-150400.3.43.1 | SUSE-SU-2026:4739-1 |
| SLES 16.0 | libsoup | 3.6.6-160000.5.1 | SUSE-SU-2026:24470-1 |
| SLE Micro 6.0 | libsoup | 3.4.2-159998.1.1 | SUSE-SU-2026:24368-1 |
| SLE Micro 5.5 | libsoup2 | 2.74.3-150400.3.43.1 | SUSE-SU-2026:4739-1 |
| SLE Micro 5.4 | libsoup2 | 2.74.3-150400.3.43.1 | SUSE-SU-2026:4739-1 |
| SLE Micro 5.3 | libsoup2 | 2.74.3-150400.3.43.1 | SUSE-SU-2026:4739-1 |
| SLE HPC 15 SP5 | libsoup | 3.0.4-150400.3.58.1 | SUSE-SU-2026:5063-1 |
| SLE HPC 15 SP5 | libsoup2 | 2.74.3-150400.3.43.1 | SUSE-SU-2026:4739-1 |
| SLE HPC 15 SP4 | libsoup | 3.0.4-150400.3.58.1 | SUSE-SU-2026:5063-1 |
| SLE HPC 15 SP4 | libsoup2 | 2.74.3-150400.3.43.1 | SUSE-SU-2026:4739-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | libsoup2 | 2.74.3-25.1 | openSUSE-SU-2026:12132-1 |
| openSUSE Leap 16.0 | libsoup | 3.6.6-160000.5.1 | openSUSE-SU-2026:22181-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | libsoup +2 | 2.72.0-6.amzn2023.0.16 | ALAS2023-2026-3212 |
| Amazon Linux 2023 | libsoup3 +2 | 3.7.3-1.amzn2023 | ALAS2023-2026-3421, ALAS2023-2026-3240 |
| Amazon Linux 2 | libsoup +1 | 2.56.0-6.amzn2.0.10 | ALAS2-2026-3998 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | libsoup | No fix yet | — |
Advisories 14
- ALAS2023-2026-3421 Important: libsoup3 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Nov 12, 2026
- SUSE-SU-2026:24470-1 Security update for libsoup SUSE / openSUSE Security Updates · Nov 4, 2026
- USN-8975-1 libsoup2.4, libsoup3 vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- SUSE-SU-2026:5062-1 Security update for libsoup SUSE / openSUSE Security Updates · Nov 3, 2026
- SUSE-SU-2026:5063-1 Security update for libsoup SUSE / openSUSE Security Updates · Nov 3, 2026
- openSUSE-SU-2026:22181-1 Security update for libsoup SUSE / openSUSE Security Updates · Oct 31, 2026
- SUSE-SU-2026:24368-1 Security update for libsoup SUSE / openSUSE Security Updates · Oct 27, 2026
- ALAS2023-2026-3240 Moderate: libsoup3 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Oct 26, 2026
- SUSE-SU-2026:4739-1 Security update for libsoup2 SUSE / openSUSE Security Updates · Oct 20, 2026
- SUSE-SU-2026:4690-1 Security update for libsoup SUSE / openSUSE Security Updates · Oct 17, 2026
- SUSE-SU-2026:4703-1 Security update for libsoup2 SUSE / openSUSE Security Updates · Oct 17, 2026
- openSUSE-SU-2026:12132-1 libsoup-2_4-1-2.74.3-25.1 on GA media SUSE / openSUSE Security Updates · Oct 15, 2026
- ALAS2-2026-3998 Important: libsoup security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Oct 12, 2026
- ALAS2023-2026-3212 Important: libsoup security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Oct 12, 2026
References
- https://access.redhat.com/security/cve/CVE-2026-103399 vdb-entry
- RHBZ#2543949 issue-tracking