CVE-2026-77815: Infinite Image Browsing Resolves Paths With normpath, Allowing Symlink Escape From Scanned Directories

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-21 · updated 2026-10-15
Weakness: CWE-59

Description

to_abs_path in scripts/iib/tool.py normalised the requested path with os.path.normpath, which collapses dot segments but does not resolve symbolic links. A symlink placed inside a scanned directory therefore satisfies the containment comparison performed by is_path_trusted in scripts/iib/api.py while pointing outside that directory, and FileResponse follows the link when serving the response, so a link created in an image directory and targeting a file such as /etc/passwd discloses that file. 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 resolves the path with os.path.realpath.

Affected products

zanllp infinite-image-browsing: through 1.8.0

References

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