CVE-2025-52477Network attack vector

Internal data disclosure via unvalidated OIDC issuer

Published Jun 26, 2025 · Updated Jun 27, 2025

SSRF in Chainguard Octo STS before 0.5.3 allows remote attackers to reach internal services through crafted OIDC token issuer fields. The Exchange path extracts an unvalidated issuer from the bearer token and passes it to provider discovery, which follows attacker-chosen endpoints. No authentication or user interaction is required, and returned errors can expose sensitive response data from otherwise unreachable internal services.

CVSS severity8.6
High
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Chainguard Octo STS before 0.5.3 allows remote attackers to reach internal services through crafted OIDC token issuer fields. The Exchange path extracts an unvalidated issuer from the bearer token and passes it to provider discovery, which follows attacker-chosen endpoints. No authentication or user interaction is required, and returned errors can expose sensitive response data from otherwise unreachable internal services.

The record

CVE
CVE-2025-52477
Published
Jun 26, 2025
Updated
Jun 27, 2025
Vendor
Chainguard
Product
Octo STS
Classifications
CWE-918, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 26, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 27, 2025Record 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=< 0.5.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Chainguard · Octo STSversion=< 0.5.3

Published CVSS scores

8.6GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A: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.

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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-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

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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