CVE-2026-86115 (CVSS 5)

Description

Sim before 0.8.14 classifies tool requests as internal based on URL prefix matching without scheme normalization, skipping SSRF validation and minting internal authentication tokens. Authenticated workflow authors can bypass external URL validation by supplying paths starting with /api/ in HTTP blocks to reach internal-only endpoints like POST /api/function/execute.

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CVSS v3.1 Score

5.0

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0030

Probability of exploitation

0.23%

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-441 CWE-441

References

Other References

https://github.com/geo-chen/oss/blob/main/sim.md https://github.com/simstudioai/sim https://github.com/simstudioai/sim/blob/v0.8.13/apps/sim/lib/auth/hybrid.ts https://github.com/simstudioai/sim/blob/v0.8.13/apps/sim/tools/index.ts https://github.com/simstudioai/sim/pull/7179 https://www.vulncheck.com/advisories/sim-before-0.8.14-confused-deputy-in-tool-url-routing-mints-an-internal-token-for-a-user-supplied-api-path

Frequently Asked Questions

What is CVE-2026-86115? +

Sim before 0.8.14 classifies tool requests as internal based on URL prefix matching without scheme normalization, skipping SSRF validation and minting internal authentication tokens. Authenticated workflow authors can bypass external URL validation by supplying paths starting with /api/ in HTTP blocks to reach internal-only endpoints like POST /api/function/execute. It has a CVSS v3.1 base score of 5.0 (MEDIUM).

How severe is CVE-2026-86115? +

CVE-2026-86115 has a CVSS v3.1 score of 5.0 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0030, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-86115? +

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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