CVE-2026-77814

HIGH
Published Aug 21, 2026 Modified Aug 21, 2026 CWE-22

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.

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CVSS v3.1 Score

7.5
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0041
Probability of exploitation
0.35%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-22 Path Traversal

References

Frequently Asked Questions

What is CVE-2026-77814? +
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. It has a CVSS v3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-77814? +
CVE-2026-77814 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0041, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-77814? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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