CVE-2026-73433: gstreamer gst-plugins-good Integer Underflow (Wrap or Wraparound)

Vulnerability summary

CVE-2026-73433 is a medium (CVSS 6.6) Integer Underflow (Wrap or Wraparound) vulnerability in gstreamer gst-plugins-good. EPSS estimates a 0.15% chance of exploitation in the next 30 days, higher than 3.6% of scored vulnerabilities.

Timeline

1. 12-08-2026
   PublishedVulnerability first disclosed.
2. 23-09-2026
   Last modifiedVulnerability information updated.

Description

A flaw was found in GStreamer gst-plugins-good (avidemux). When parsing FUJIFILM metadata in an AVI strd chunk, gst_avi_demux_parse_strd() decrements a remaining-length counter by fixed offsets (98 and 10 bytes) without verifying sufficient data remains. For crafted strd payloads of exactly 106 or 107 bytes, the counter underflows to a very large unsigned value, causing subsequent null-terminated string scanning to read far beyond the allocated heap buffer. Date-format normalization may also write beyond the buffer end. Confirmed impacts include heap out-of-bounds read, out-of-bounds write, heap information disclosure (adjacent data appearing in parsed metadata), and application crash/denial of service. The avidemux element is auto-plugged by playbin, decodebin, and gst-discoverer, so opening or previewing a crafted AVI is sufficient to trigger the issue. Fixed upstream in gst-plugins-good 1.28.6 (GStreamer-SA-2026-0072).

• CWE-191Integer Underflow (Wrap or Wraparound)The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.