CVE-2026-53507

oasdiff actions resolve external $refs by default, enabling SSRF and disclosure of structured files on pull-request runs

Published Aug 31, 2026 CVSS 4.0 · 8.3 High EPSS < 1% KEV · Not listed
Description
oasdiff-action is a GitHub Action that detects breaking changes in OpenAPI specs and post a review on every pull request. Before version 0.0.51, the oasdiff actions resolved external $refs in the OpenAPI spec by default (allow-external-refs: true). When an action runs on a pull request whose spec is attacker-controlled — most importantly fork pull requests on public repositories — a $ref in that spec is fetched/read on the runner with no interaction required, enabling SSRF and disclosure of structured files on the runner. This issue has been patched in version 0.0.51.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Oasdiff
Oasdiff oasdiff-action
Vendors & Products Oasdiff
Oasdiff oasdiff-action
Type Values Removed Values Added
Description oasdiff-action is a GitHub Action that detects breaking changes in OpenAPI specs and post a review on every pull request. Before version 0.0.51, the oasdiff actions resolved external $refs in the OpenAPI spec by default (allow-external-refs: true). When an action runs on a pull request whose spec is attacker-controlled — most importantly fork pull requests on public repositories — a $ref in that spec is fetched/read on the runner with no interaction required, enabling SSRF and disclosure of structured files on the runner. This issue has been patched in version 0.0.51.
Title oasdiff actions resolve external $refs by default, enabling SSRF and disclosure of structured files on pull-request runs
Weaknesses CWE-1188
CWE-200
CWE-918
References
Metrics cvssV4_0

{'score': 8.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 1, 2026, 2:46 PM
Reserved
Jun 9, 2026, 5:05 PM
Status
Deferred
Published
Aug 31, 2026, 7:16 PM
Modified
Sep 9, 2026, 9:09 PM