CVE-2026-6324 | Libsoup: libsoup: http request smuggling via unsigned to signed conversion error

A flaw was found in libsoup. A remote attacker could exploit an unsigned to signed conversion error in the `soup_body_input_stream_read_chunked()` function by sending a malicious HTTP request. This vulnerability occurs when libsoup operates behind a non-libsoup proxy server or as a proxy in front of a non-libsoup backend server. Successful exploitation can allow an attacker to bypass security controls, poison web caches, or gain unauthorized access.

Published: 2026-05-29 Last update: 2026-05-29 Assigner: [email protected] Source: [email protected]
NVD Status：Awaiting Analysis，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-6324 is rated Low Risk (25.4/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.06%). 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-2026-6324

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 2026-06-04 0.04% 0.06% +0.02%
2 2026-05-29 — 0.04% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-6324

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:L/A:N 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:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 2.5 [email protected]

Weakness enumeration for CVE-2026-6324

GitHub Security Advisory for CVE-2026-6324

GHSA-2637-3gxc-qg4f · Severity: medium — A flaw was found in libsoup. A remote attacker could exploit an unsigned to signed conversion...

OS Trackers for CVE-2026-6324

vendor priority summary link
debian not yet assigned CVE-2026-6324 not yet assigned priority: Debian including 2 source packages (libsoup2.4, libsoup3), 7 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 7. https://security-tracker.debian.org/tracker/CVE-2026-6324
suse high — https://www.suse.com/security/cve/CVE-2026-6324/
ubuntu medium CVE-2026-6324 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-2026-6324

Affected software / configurations for CVE-2026-6324

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-6324

cvelogic Threat Intelligence