CVE-2026-12549

Libsoup: incomplete fix for cve-2026-2443: range suffix overflow in libsoup soupserver

MEDIUM
4.8
CVSS Score
Published: June 22, 2026 at 01:55 PM UTC
Updated: July 8, 2026 at 03:29 PM UTC
2 products affected across 2 vendorsEnterprise LinuxLibsoup

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Severity
MEDIUM4.8
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

All versions
Vendor states this is fixed in 6 (unknown)
Vendor states this is fixed in 7 (unknown)

References (4)

VDB Entryx_refsource_REDHATVendor AdvisoryMitigation
Source: cverecord
https://access.redhat.com/security/cve/CVE-2026-12549
Technical Descriptionx_refsource_REDHATVendor AdvisoryMitigation
Source: cverecord
https://access.redhat.com/security/cve/cve-2026-0716
Issue Trackingx_refsource_REDHATVendor Advisory
Source: cverecord
https://bugzilla.redhat.com/show_bug.cgi?id=2489999
ExploitIssue TrackingPatchVendor Advisory
Source: cverecord
https://gitlab.gnome.org/GNOME/libsoup/-/work_items/516

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.8MEDIUMredhat
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-805

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