CVE-2026-12549 | Libsoup: incomplete fix for cve-2026-2443: range suffix overflow in libsoup soupserver

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.

Published: 2026-06-22 Last update: 2026-06-23 Assigner: [email protected] Source: [email protected]
NVD Status：Awaiting Analysis，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-12549 is rated Low Risk (27.3/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.32%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-12549

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-23 — 0.32% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-12549

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.8 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.2 2.5 [email protected]

Weakness enumeration for CVE-2026-12549

GitHub Security Advisory for CVE-2026-12549

GHSA-7gwx-vgp2-4hmg · Severity: medium — The fix for CVE-2026-2443 was regressed by a subsequent rework commit that replaced specific...

OS Trackers for CVE-2026-12549

vendor priority summary link
debian unimportant CVE-2026-12549 unimportant priority: Debian including 2 source packages (libsoup2.4, libsoup3), 7 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 3. https://security-tracker.debian.org/tracker/CVE-2026-12549
suse medium — https://www.suse.com/security/cve/CVE-2026-12549/
ubuntu medium CVE-2026-12549 medium priority: Ubuntu including 2 source packages (libsoup2.4, libsoup3), 13 status rows across 8 suites (bionic, focal, jammy, noble, questing, resolute, upstream, xenial): needs-triage 13. https://ubuntu.com/security/CVE-2026-12549

Affected software / configurations for CVE-2026-12549

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-12549

cvelogic Threat Intelligence