CVE-2026-12548: A heap out-of-bounds read flaw was found in libsoup

Routine

MEDIUM 4.2WATCHLISTMITIGATEMITIGATE

CVE-2026-12548 is a medium-severity flaw (CVSS 4.2) affecting libsoup, enterprise linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	4.2 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 84%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-07-21
Last modified	2026-10-24

Publisher (CNA): Red Hat, Inc. · Vendor: gnome · redhat

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-21 19:17 UTCPublished CVE record published
2026-10-24 19:10 UTCUpdated Record last modified

gnome libsoup MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy libsoup || rpm -q libsoup || libsoup --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

redhat enterprise linux MITIGATE

Affected: 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Advisories and coverage

Official advisories

Amazon Linux 2023 ALAS: ALAS2023-2026-3154 (medium): libsoup 2026-10-12
Amazon Linux 2 ALAS: ALAS2-2026-3970 (medium): libsoup 2026-10-12
Amazon Linux 2023 ALAS: ALAS2023-2026-3144 (important): libsoup3 2026-09-29

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-12548?

libsoup: mitigate or apply the listed mitigation; enterprise linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-12548 being exploited?

CVE-2026-12548 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-12548 affect?

CVE-2026-12548 affects libsoup, enterprise linux. Severity is medium (CVSS 4.2). 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 bu

How urgent is CVE-2026-12548?

Priority 29/100. Public exploit reference; On your watchlist

Related CVEs

CVE-2026-102560 HIGH 8.6 UPGRADE MITIGATE A flaw was found in libsoup

References

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