Vulnerability record · CVE-2026-77814 · published 21 August 2026
CVE-2026-77814: Path traversal vulnerability
is_path_trusted in scripts/iib/api.py compares the requested path against each allowed parent directory with path.startswith(parent_path), without appending a path separator. A directory whose name merely begins with an allowed path therefore satisfies the comparison, so where /data/images is allowed a request for /data/images_private/secret.txt is treated as trusted and served by FileResponse, disclosing files the confinement was meant to exclude. Whether the check applies depends on get_enable_access_control in scripts/iib/tool.py: it returns true when IIB_ACCESS_CONTROL is set to enable, false when set to disable, and otherwise true when the host Stable Diffusion WebUI was started with share, ngrok, listen or server_name, falling back to false. Confinement is therefore active in the network-exposed WebUI deployments that rely on it, while a standalone run with no such option serves every readable file regardless of this flaw. The fix compares against parent_path joined with os.sep.
Description
is_path_trusted in scripts/iib/api.py compares the requested path against each allowed parent directory with path.startswith(parent_path), without appending a path separator. A directory whose name merely begins with an allowed path therefore satisfies the comparison, so where /data/images is allowed a request for /data/images_private/secret.txt is treated as trusted and served by FileResponse, disclosing files the confinement was meant to exclude. Whether the check applies depends on get_enable_access_control in scripts/iib/tool.py: it returns true when IIB_ACCESS_CONTROL is set to enable, false when set to disable, and otherwise true when the host Stable Diffusion WebUI was started with share, ngrok, listen or server_name, falling back to false. Confinement is therefore active in the network-exposed WebUI deployments that rely on it, while a standalone run with no such option serves every readable file regardless of this flaw. The fix compares against parent_path joined with os.sep.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:
References
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2026-77814), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.
