CVE-2026-12549: Libsoup: incomplete fix for cve-2026-2443: range suffix overflow in libsoup soupserver
https://gitlab.gnome.org/GNOME/libsoup/-/workitems/516 https://redhat.atlassian.net/browse/PSIRTSUPT-8846
Other sources
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.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-12549?
CVE-2026-12549 has a medium severity rating of 4.8.
What software is affected by CVE-2026-12549?
CVE-2026-12549 affects Gnome libsoup.
How do I fix CVE-2026-12549?
To fix CVE-2026-12549, update to the latest version of Gnome libsoup that addresses this vulnerability.
What causes CVE-2026-12549?
CVE-2026-12549 is caused by an incomplete fix for CVE-2026-2443, allowing improper handling of Range requests.
What is the impact of CVE-2026-12549?
The impact of CVE-2026-12549 includes potential unhandled negative start values leading to unexpected behavior in libsoup.