CVE-2026-12549
Libsoup: incomplete fix for cve-2026-2443: range suffix overflow in libsoup soupserver
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.
INFO
Published Date :
June 22, 2026, 4:16 p.m.
Last Modified :
July 8, 2026, 3:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-12549
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 53f830b8-0a3f-465b-8143-3b8a9948e749 | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Revert the rework commit that removed overflow checks.
- Reimplement specific overflow checks for Range requests.
- Ensure negative start values are properly clamped.
- Fix malformed HTTP 206 responses.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-12549.
| URL | Resource |
|---|---|
| https://access.redhat.com/security/cve/CVE-2026-12549 | Vendor Advisory Mitigation |
| https://access.redhat.com/security/cve/cve-2026-0716 | Vendor Advisory Mitigation |
| https://bugzilla.redhat.com/show_bug.cgi?id=2489999 | Issue Tracking Vendor Advisory |
| https://gitlab.gnome.org/GNOME/libsoup/-/work_items/516 | Exploit Issue Tracking Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-12549 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-12549
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-12549 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-12549 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 08, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* Added CPE Configuration OR *cpe:2.3:a:gnome:libsoup:-:*:*:*:*:*:*:* Added Reference Type Red Hat, Inc.: https://access.redhat.com/security/cve/cve-2026-0716 Types: Mitigation, Vendor Advisory Added Reference Type Red Hat, Inc.: https://access.redhat.com/security/cve/CVE-2026-12549 Types: Mitigation, Vendor Advisory Added Reference Type Red Hat, Inc.: https://bugzilla.redhat.com/show_bug.cgi?id=2489999 Types: Issue Tracking, Vendor Advisory Added Reference Type Red Hat, Inc.: https://gitlab.gnome.org/GNOME/libsoup/-/work_items/516 Types: Exploit, Issue Tracking, Patch, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 23, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-12549', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-23T14:05:45.451175Z'} -
New CVE Received by [email protected]
Jun. 22, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'packageName': 'libsoup3', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:6'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 6', 'packageName': 'libsoup', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unknown'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 7', 'packageName': 'libsoup', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unknown'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'packageName': 'libsoup', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:9'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 9', 'packageName': 'libsoup', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}] Added 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. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L Added CWE CWE-805 Added Reference https://access.redhat.com/security/cve/cve-2026-0716 Added Reference https://access.redhat.com/security/cve/CVE-2026-12549 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2489999 Added Reference https://gitlab.gnome.org/GNOME/libsoup/-/work_items/516