EUVD-2026-68729Severity by source
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network-triggered via fork PR with no auth (AV:N/PR:N), but requires fork workflow to be enabled (AC:H); scope change to runner secrets/metadata justifies S:C and C:H.
Primary rating from Vendor (GitHub_M).
CVSS VectorVendor: GitHub_M
Lifecycle Timeline
5DescriptionCVE.org
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.
AnalysisAI
Server-Side Request Forgery and structured file disclosure in oasdiff-action prior to version 0.0.51 allows unauthenticated remote attackers to make the GitHub Actions runner fetch arbitrary URLs or read filesystem paths by embedding malicious $ref entries in an attacker-controlled OpenAPI spec. The vulnerability is directly exploitable via fork pull requests on public repositories, requiring no interaction from maintainers beyond the normal CI workflow execution. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The following specific conditions are required: (1) the target repository uses oasdiff-action at any version before 0.0.51; (2) the GitHub Actions workflow is configured with a `pull_request` or `pull_request_target` trigger that executes on fork-originated PRs (the default for public repositories); (3) the `allow-external-refs` input is not explicitly set to `false` (i.e., the pre-0.0.51 default of `true` is in effect). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 score of 8.3 with AV:N/AC:L/AT:P/PR:N/UI:N/VC:H reflects the real-world severity accurately. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade to oasdiff-action version 0.0.51 or later, which changes the `allow-external-refs` default to `false`, blocking external ref resolution for untrusted fork PRs without any configuration change required. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify all repositories using oasdiff-action and restrict the action to trusted branches only by modifying workflow permissions to require approval before fork PRs execute. …
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Threat intelligence, references, and detailed analysis are available after sign-in.
Same weakness CWE-200 – Information Exposure
View allSame technique Information Disclosure
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External POC / Exploit Code
Leaving vuln.today