CVE-2025-54864Network attack vector

Unauthenticated service interruption via unsigned webhook evaluations

Published Aug 12, 2025 · Updated Aug 12, 2025

Missing authentication in NixOS Hydra before f7bda02 allows remote attackers to trigger costly evaluations through webhook requests. The /api/push-github and /api/push-gitea handlers accept unsigned POST bodies instead of verifying forge HMAC-SHA256 signatures. No account or user interaction is required; repeated large evaluations can exhaust evaluator resources and interrupt the service.

CVSS severity6.9
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authentication in NixOS Hydra before f7bda02 allows remote attackers to trigger costly evaluations through webhook requests. The /api/push-github and /api/push-gitea handlers accept unsigned POST bodies instead of verifying forge HMAC-SHA256 signatures. No account or user interaction is required; repeated large evaluations can exhaust evaluator resources and interrupt the service.

The record

CVE
CVE-2025-54864
Published
Aug 12, 2025
Updated
Aug 12, 2025
Vendor
NixOS
Product
Hydra
Classifications
CWE-306, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 12, 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=< f7bda020c6144913f134ec616783e57817f7686f

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

NixOS · Hydraversion=< f7bda020c6144913f134ec616783e57817f7686f

Published CVSS scores

6.9GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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-306Missing Authentication for Critical Function
T1499.003Application Exhaustion Flood

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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