Vulnerability in @fedify/fedify (CVE-2026-50131)
Summary
Vulnerability in @fedify/fedify (CVE-2026-50131). Confidential information can be exposed externally. Mitigation: upgrade to 2.2.4 or later.
Original description
The description as published by the source.
Summary
Fedify previously addressed SSRF/internal network access in GHSA-p9cg-vqcc-grcx by adding public URL validation before runtime document and media fetching. However, the current IPv4 validation logic appears incomplete.
The validatePublicUrl() protection relies on isValidPublicIPv4Address() to reject non-public IPv4 destinations. The function blocks common private and local ranges such as 10.0.0.0/8, 127.0.0.0/8, 169.254.0.0/16, 172.16.0.0/12, and 192.168.0.0/16, but it still treats several special-use, reserved, multicast, benchmarking, and carrier-grade NAT IPv4 ranges as valid public destinations.
Because this validation is used as an SSRF defense before outbound fetches, this appears to be an incomplete mitigation or bypass class for the previous SSRF issue.
I tested this against the current repository code at unreleased version 2.3.0. I used >=0.11.2, <=2.2.3 as the suspected affected range because 0.11.2 is listed as a patched version for GHSA-p9cg-vqcc-grcx, and this report concerns the post-fix validation logic. Maintainers may adjust the exact affected range.
Why this is not a duplicate of GHSA-p9cg-vqcc-grcx
GHSA-p9cg-vqcc-grcx covered the original behavior where Fedify fetched ActivityPub object, activity, document, and media URLs without first ensuring that the resolved destination was public.
This report is about the post-fix validation logic. The current mitigation now performs public URL/IP validation, but the IPv4 classifi…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-50131 has been found in @fedify/fedify.
Confidential information can be exposed externally. CVSS score: 8.6/10.
What to do: upgrade @fedify/fedify to 2.2.4 or later.
If unsure, ask your IT team or search "@fedify/fedify CVE-2026-50131" on the vendor's site.
CVE-2026-50131 (@fedify/fedify) — CWE-1286 / CVSS v3 8.6
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 2.2.4 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-1286) exists in @fedify/fedify.
Check the vendor advisory for the affected versions of @fedify/fedify.
Severity: High (CVSS 8.6/10). Confidential information can be exposed externally.
Update to 2.2.4.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r '@fedify/fedify' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r '@fedify/fedify' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
@fedify/fedifyを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade @fedify/fedify to 2.2.4ステージング環境で 2.2.4 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com