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Fencer Vulns
low 3.7

CVE-2026-2708 json

Libsoup: libsoup: http request smuggling via duplicate content-length headers

published 2026-04-23 6 mo ago modified 2026-11-06 2 d ago also EUVD-2026-25306

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 25%
public exploits
0
none known

Summary

A request smuggling vulnerability exists in libsoup's HTTP/1 header parsing logic. The soup_message_headers_append_common() function in libsoup/soup-message-headers.c unconditionally appends each header value without validating for duplicate or conflicting Content-Length fields. This allows an attacker to send HTTP requests containing multiple Content-Length headers with differing values.

Patch / fix

  • libsoup Linux Micro 6.0 3.4.2-159998.1.1
  • libsoup2 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +8 more 2.74.3-150400.3.43.1
  • libsoup2 SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Basesystem 15 SP7 2.74.3-150600.4.42.1
  • libsoup SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Basesystem 15 SP7 3.4.4-150600.3.59.1
  • libsoup SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 3.0.4-150400.3.55.1
  • libsoup SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 3.6.6-160000.1.1
  • libsoup2 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +8 more 2.74.2-150400.3.31.1
  • libsoup Linux Micro 6.1 3.4.4-slfo.1.1_7.1

suse advisories SUSE-SU-2026:24368-1SUSE-SU-2026:4739-1SUSE-SU-2026:4703-1SUSE-SU-2026:4631-1SUSE-SU-2026:4616-1SUSE-SU-2026:20752-1

  • libsoup openSUSE Leap 16.0 3.6.6-160000.1.1
  • libsoup2 openSUSE Leap 16.0 2.74.3-160000.4.1
  • libsoup openSUSE Tumbleweed 3.6.6-1.1
  • libsoup2 openSUSE Tumbleweed 2.74.3-17.1

opensuse advisories openSUSE-SU-2026:20384-1openSUSE-SU-2026:20354-1openSUSE-SU-2026:10245-1openSUSE-SU-2026:10246-1

  • libsoup Azure Linux 3.0 3.4.4-16

azure linux advisories AZL-84683

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-2708 updated cvss 3.7

libsoup: libsoup: HTTP Request Smuggling via Duplicate Content-Length Headers

  • Red Hat Enterprise Linux 6 libsoup Red Hat Enterprise Linux 7 libsoup Red Hat Enterprise Linux 8 libsoup Red Hat Enterprise Linux 9 libsoup Red Hat Enterprise Linux 10 libsoup3
    affected: no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • gitlab.gnome.org https://gitlab.gnome.org/GNOME/libsoup/-/issues/500 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

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

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.