oasdiff actions resolve external $refs by default, enabling SSRF and disclosure of structured files on pull-request runs (CVE-2026-53507) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-53507

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

Answer in brief

CVE-2026-53507 records a Unknown severity vulnerability in oasdiff actions resolve external $refs by default, enabling SSRF and disclosure of structured files on pull-request runs. The current sources do not mark it as known exploited. The current feed maps oasdiff/oasdiff-action (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 31, 2026Updated Aug 31, 2026Source checked Aug 31, 2026First seen by HOL Aug 31, 2026Material review Aug 31, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps oasdiff/oasdiff-action (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
oasdiff/oasdiff-actiongeneric	< 0.0.51	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for oasdiff/oasdiff-action.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Aug 31, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 31, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 31, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.