Skip to content
Fencer Vulns
medium 4.2

CVE-2026-12548 json

Libsoup: heap out-of-bounds read in libsoup due to integer truncation

published 2026-07-21 3 mo ago modified 2026-11-05 3 d ago also EUVD-2026-46363

cvss
4.2
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 17%
public exploits
0
none known

Summary

A heap out-of-bounds read flaw was found in libsoup. When parsing multipart HTTP messages, an integer type mismatch between the caller and soup_headers_parse() can cause the length parameter to be incorrectly truncated, leading to a heap buffer over-read. A remote attacker could use this flaw to crash an application using libsoup or potentially disclose heap memory contents.

Patch / fix

  • libsoup3 Ubuntu 24.04 LTS 3.4.4-5ubuntu0.10
  • libsoup3 Ubuntu 26.10 3.6.6-1ubuntu3.1
  • libsoup3 Ubuntu 26.04 LTS 3.6.6-1ubuntu0.2
  • libsoup2.4 Ubuntu 22.04 LTS 2.74.2-3ubuntu0.10
  • libsoup2.4 Ubuntu 24.04 LTS 2.74.3-6ubuntu1.10
  • libsoup3 Ubuntu Pro 22.04 LTS 3.0.7-0ubuntu1+esm10
  • libsoup2.4 Ubuntu Pro 16.04 LTS 2.52.2-1ubuntu0.3+esm9
  • libsoup2.4 Ubuntu Pro 18.04 LTS 2.62.1-1ubuntu0.4+esm10

ubuntu advisories UBUNTU-CVE-2026-12548

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libsoup SLES for SAP applications 16.0, SLES 16.0 3.6.6-160000.5.1
  • 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 SLE Module for Basesystem 15 SP7 3.4.4-150600.3.50.1
  • libsoup2 SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Basesystem 15 SP7 2.74.3-150600.4.39.1

suse advisories SUSE-SU-2026:24470-1SUSE-SU-2026:24368-1SUSE-SU-2026:4739-1SUSE-SU-2026:4703-1SUSE-SU-2026:4690-1SUSE-SU-2026:4631-1

  • libsoup openSUSE Leap 16.0 3.6.6-160000.5.1
  • libsoup openSUSE Tumbleweed 3.6.6-8.1
  • libsoup2 openSUSE Tumbleweed 2.74.3-22.1

opensuse advisories openSUSE-SU-2026:22181-1openSUSE-SU-2026:11596-1openSUSE-SU-2026:11576-1

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-2026-12548 updated cvss 4.2

libsoup: Heap out-of-bounds read in libsoup due to integer truncation

  • 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
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • gitlab.gnome.org https://gitlab.gnome.org/GNOME/libsoup/-/work_items/512 referenced PoC, tagged "exploit" by a source, unverified
  • bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=2489996 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:L

Affected products

  • Red Hat Red Hat Enterprise Linux 10

Classification

Weakness

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.