# CVE-2026-53508

## Summary

- **CVE ID:** CVE-2026-53508
- **Severity:** MEDIUM
- **CVSS Score:** 6 (CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N)
- **CWE:** CWE-73, CWE-693, CWE-918
- **Published:** Aug 31, 2026
- **Last Modified:** Aug 31, 2026

## Description

oasdiff is a command-line and Go package that compares and detects breaking changes in OpenAPI specs. From version 1.13.2 through version 1.18.0, oasdiff did not enforce --allow-external-refs=false (library: openapi3.Loader.IsExternalRefsAllowed = false) when loading a spec from a git revision (the rev:path form, e.g. main:openapi.yaml). External $refs were resolved on that load path even when external refs were explicitly disabled, so the mitigation silently did not apply there. This issue has been patched in version 1.18.1.

## Affected Products

- oasdiff — oasdiff (>= 1.13.2, < 1.18.1)

## References

- [CNA](https://github.com/oasdiff/oasdiff/security/advisories/GHSA-2jcc-mxv7-p3f9)
- [CNA](https://github.com/oasdiff/oasdiff/pull/832)
- [CNA](https://github.com/oasdiff/oasdiff/pull/974)
- [CNA](https://github.com/oasdiff/oasdiff/pull/975)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.29%
- **EPSS Percentile:** 21.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._