How severe is CVE-2025-52477?

CVE-2025-52477 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2025-52477 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-52477?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-52477 have an EU (EUVD) identifier?

Yes. CVE-2025-52477 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-19216.

When was CVE-2025-52477 published?

CVE-2025-52477 was published on 2025-06-26 and last updated on 2026-06-17.

CVE-2025-52477

CVE-2025-52477 is a high-severity vulnerability with a CVSS 3.x base score of 8.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-918.

Key facts

Severity: High (CVSS 3.x base score 8.6)
EPSS exploit prediction: 0% (33rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-19216
Weakness: CWE-918
Published: 2025-06-26
Last modified: 2026-06-17

Description

Octo-STS is a GitHub App that acts like a Security Token Service (STS) for the GitHub API. Octo-STS versions before v0.5.3 are vulnerable to unauthenticated SSRF by abusing fields in OpenID Connect tokens. Malicious tokens were shown to trigger internal network requests which could reflect error logs with sensitive information. Upgrade to v0.5.3 to resolve this issue. This version includes patch sets to sanitize input and redact logging.

Frequently asked questions

What is CVE-2025-52477?: Octo-STS is a GitHub App that acts like a Security Token Service (STS) for the GitHub API. Octo-STS versions before v0.5.3 are vulnerable to unauthenticated SSRF by abusing fields in OpenID Connect tokens. Malicious tokens were shown to trigger internal network requests which could reflect error logs with sensitive information. Upgrade to v0.5.3 to resolve this issue. This version includes patch sets to sanitize input and redact logging.
How severe is CVE-2025-52477?: CVE-2025-52477 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2025-52477 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-52477?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-52477 have an EU (EUVD) identifier?: Yes. CVE-2025-52477 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-19216.
When was CVE-2025-52477 published?: CVE-2025-52477 was published on 2025-06-26 and last updated on 2026-06-17.

References

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