SSRF (Server-Side Request Forgery) in mcp-searxng (CVE-2026-54688)
Summary
SSRF in mcp-searxng (CVE-2026-54688). Confidential information can be exposed externally. Mitigation: upgrade to 1.2.1 or later.
Original description
The description as published by the source.
Ref: https://github.com/ihor-sokoliuk/mcp-searxng/issues/87#issuecomment-4645453694
Summary
The web_url_read tool fetches a caller-supplied URL server-side and converts it to markdown. An SSRF guard (assertUrlAllowed, which blocks private/loopback/metadata addresses) exists but runs only when MCP_HTTP_HARDEN=true, which is off by default. So in the default configuration there is no internal-address filtering, and an attacker who can influence the URL can make the server fetch internal services and cloud metadata and return their content. Confirmed on 1.1.0 (default config): web_url_read fetched a local internal sentinel and returned its content.
Details
dist/index.js (around lines 90-101): web_url_read calls fetchAndConvertToMarkdown on the caller URL. dist/url-reader.js (around lines 44-52): assertUrlAllowed performs the private-IP/loopback check, but only when the hardening flag is set; dist/http-security.js (around line 11) defaults MCP_HTTP_HARDEN to off. With the default config the check is skipped entirely. Even when enabled, the check is literal-hostname based with no DNS-rebinding or redirect re-check (the fetch follows redirects). file:// is rejected, so this is HTTP/HTTPS SSRF.
PoC
Re-validated on mcp-searxng 1.1.0 over MCP stdio in the default configuration (MCP_HTTP_HARDEN not set):
tools: searxng_web_search, web_url_read
web_url_read({ url: "http://127.0.0.1:/internal" }) -> server fetched the internal sentinel; SSRF: CONFIRMED
The server f…
Source: GitHub Security Advisories (Global) 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-2026-54688 has been found in mcp-searxng.
Confidential information can be exposed externally. CVSS score: 6.5/10.
What to do: upgrade mcp-searxng to 1.2.1 or later.
If unsure, ask your IT team or search "mcp-searxng CVE-2026-54688" on the vendor's site.
CVE-2026-54688 (mcp-searxng) — CWE-918 / CVSS v3 6.5
Attack vector: remote (network-reachable) / unauthenticated
Patched: 1.2.1 — 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.
SSRF (CWE-918) exists in mcp-searxng.
Check the vendor advisory for the affected versions of mcp-searxng.
Severity: Medium (CVSS 6.5/10). Confidential information can be exposed externally.
Update to 1.2.1.
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 'mcp-searxng' . 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 'mcp-searxng' . | 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
mcp-searxng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 mcp-searxng to 1.2.1ステージング環境で 1.2.1 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
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web security-advisories@github.com
- web security-advisories@github.com