CVE-2026-12549: gnome libsoup

Vulnerability summary

CVE-2026-12549 is a medium (CVSS 4.8) vulnerability in gnome libsoup. EPSS estimates a 0.36% chance of exploitation in the next 30 days, higher than 27.9% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 22-06-2026
   PublishedVulnerability first disclosed.
2. 23-06-2026
   Last modifiedVulnerability information updated.

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.

• CWE-805Buffer Access with Incorrect Length ValueThe product uses a sequential operation to read or write a buffer, but it uses an incorrect length value that causes it to access memory that is outside of the bounds of the buffer.