CVE-2026-53507Network attack vector

Runner file disclosure and SSRF via external refs

Published Aug 31, 2026 · Updated Sep 1, 2026

SSRF and information disclosure in oasdiff-action before 0.0.51 allow remote attackers to access runner resources through pull requests. The action leaves allow-external-refs enabled by default and resolves attacker-controlled HTTP and file $refs on the CI runner. Exposure requires untrusted pull-request specifications, especially fork submissions, and permits requests to internal services or disclosure of readable structured YAML or JSON through action output.

CVSS severity8.3
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF and information disclosure in oasdiff-action before 0.0.51 allow remote attackers to access runner resources through pull requests. The action leaves allow-external-refs enabled by default and resolves attacker-controlled HTTP and file $refs on the CI runner. Exposure requires untrusted pull-request specifications, especially fork submissions, and permits requests to internal services or disclosure of readable structured YAML or JSON through action output.

The record

CVE
CVE-2026-53507
Published
Aug 31, 2026
Updated
Sep 1, 2026
Vendor
oasdiff
Product
oasdiff-action
Classifications
CWE-1188, CWE-200, CWE-918, T1005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.0.51

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

oasdiff · oasdiff-actionversion=< 0.0.51

Published CVSS scores

8.3GitHub CNACVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1188Initialization of a Resource with an Insecure Default
CWE-200Exposure of Sensitive Information to an Unauthorized Actor
CWE-918Server-Side Request Forgery (SSRF)
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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