CVE-2026-12549: The fix for CVE-2026-2443 was regressed by a subsequent rework commit that replaced specific overflow checks w

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MEDIUM 4.8REMOTEWATCHLISTMITIGATEMITIGATE

CVE-2026-12549 is a medium-severity flaw (CVSS 4.8) affecting enterprise linux, libsoup. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The fix for CVE-2026-2443 was regressed by a subsequent rework commit that replaced specific overflow checks with a general signed comparison. When a client sends a Range request with a suffix length exceeding the content size, the resulting negative start value is not properly clamped, leading to malformed HTTP 206 responses and log flooding.

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

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

Risk facts

CVSS score	4.8 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 71%)
CISA exploited list	No
Weakness	CWE-805
Published	2026-06-22
Last modified	2026-07-08

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

Last updated 2026-07-08 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-22 16:16 UTCPublished CVE record published
2026-07-08 15:10 UTCUpdated Record last modified

redhat enterprise linux MITIGATE

Affected: 6.0 · 7.0 · 8.0 · 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.0

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.

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.

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

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-2026-12549?

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

Is CVE-2026-12549 being exploited?

CVE-2026-12549 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-2026-12549 affect?

CVE-2026-12549 affects enterprise linux, libsoup. Severity is medium (CVSS 4.8). The fix for CVE-2026-2443 was regressed by a subsequent rework commit that replaced specific overflow checks with a general signed comparison. When a client sends a Range request with a suffix length exceeding the content size, the resultin

How urgent is CVE-2026-12549?

Priority 39/100. Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Related CVEs

CVE-2026-13097 HIGH 8.7 MITIGATE DOWNGRADE A privilege escalation flaw was found in FreeIPA
CVE-2026-73198 HIGH 7.5 MITIGATE UPGRADE A flaw was found in FreeIPA
CVE-2026-73197 HIGH 7.5 MITIGATE UPGRADE A flaw was found in FreeIPA
CVE-2026-11861 CRITICAL 9.6 UPGRADE MITIGATE A flaw was found in FreeIPA
CVE-2026-73196 MEDIUM 4.3 MITIGATE UPGRADE A flaw was found in FreeIPA

References

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