Unauthenticated SSRF via unsanitized WebFinger domain
Published Feb 10, 2025 · Updated Feb 11, 2025
SSRF in Lemmy 0.19.8 and earlier allows remote attackers to make arbitrary GET requests to internal services through WebFinger input. The activitypub_federation WebFinger resolver interpolates the account domain into a request URL, while verify_url_valid compares literal hostnames without resolving addresses or rejecting path, query, fragment, or port syntax. No authentication or user interaction is required; the server becomes a blind request proxy to localhost, internal-network, or cloud-metadata endpoints.
Summary
What happened
SSRF in Lemmy 0.19.8 and earlier allows remote attackers to make arbitrary GET requests to internal services through WebFinger input. The activitypub_federation WebFinger resolver interpolates the account domain into a request URL, while verify_url_valid compares literal hostnames without resolving addresses or rejecting path, query, fragment, or port syntax. No authentication or user interaction is required; the server becomes a blind request proxy to localhost, internal-network, or cloud-metadata endpoints.
The record
- CVE
- CVE-2025-25194
- Published
- Feb 10, 2025
- Updated
- Feb 11, 2025
- Vendor
- LemmyNet
- Product
- Lemmy
- Classifications
- CWE-918, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 10, 2025CVE publishedPublication date reported by the CVE source.
- Feb 11, 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.
- Affected versionversion=<= 0.19.8
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- WebFinger localhost and domain-block bypass proof of conceptproof of concept · demonstrated
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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