Denial of service via unbounded redirect recursion
Published Apr 6, 2026 · Updated Apr 6, 2026
Denial of service in affected Fedify releases allows remote attackers to exhaust server resources through attacker-controlled URLs. Its remote and authenticated document loaders recursively call the loader on each 3xx Location value without a redirect cap or visited-URL tracking. Control of a remote keyId or actor URL is sufficient to amplify one inbound request into repeated outbound requests that consume worker time, connections, CPU, and bandwidth.
Summary
What happened
Denial of service in affected Fedify releases allows remote attackers to exhaust server resources through attacker-controlled URLs. Its remote and authenticated document loaders recursively call the loader on each 3xx Location value without a redirect cap or visited-URL tracking. Control of a remote keyId or actor URL is sufficient to amplify one inbound request into repeated outbound requests that consume worker time, connections, CPU, and bandwidth.
The record
- CVE
- CVE-2026-34148
- Published
- Apr 6, 2026
- Updated
- Apr 6, 2026
- Vendor
- Fedify
- Product
- Fedify
- Classifications
- CWE-400, CWE-770, T1499.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 6, 2026CVE publishedPublication date reported by the CVE source.
- Apr 6, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 1.10.0, < 1.10.5
- Affected versionversion=< 1.9.6
- Affected versionversion=>= 2.0.0, < 2.0.8
- Affected versionversion=>= 2.1.0, < 2.1.1
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
- GHSA minimal redirect-loop reproductionproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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