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TI-2026-42087 Aliases CVE-2026-58483

mcp-searxng: Unbounded Response Body Read Bypasses URL Size Limit in `web_url_read`

Priority HIGH 72CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-400.

Summary

mcp-searxng is a Model Context Protocol server that gives AI assistants web search and URL-reading capabilities through SearXNG. Prior to 1.7.1, web_url_read in src/index.ts passes a caller-supplied URL to readUrlContent() in src/url-reader.ts, where checkContentLength() treats a missing Content-Length header as an inconclusive preflight and the normal and error paths then consume the complete body with response.text(). A server that omits Content-Length can therefore bypass URL_READ_MAX_CONTENT_LENGTH_BYTES and force unbounded memory use. The resulting string is also processed by NodeHtmlMarkdown.translate(), increasing CPU consumption and allowing an unauthenticated HTTP client to cause denial of service. This issue is fixed in version 1.7.1.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0067 52nd percentileScored 2026-11-07
Fix Fixed mcp-searxng (ihor-sokoliuk): 1.7.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ihor-sokoliukmcp-searxngbefore 1.7.11.7.1Patch availableCNA
  • mcp-searxng Vendorihor-sokoliuk Affected before 1.7.1 Fixed in 1.7.1 Patch available CNA

Remediation

  • Fix · CNA mcp-searxng (ihor-sokoliuk) Fixed in 1.7.1

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-58483

References

Other 4

  • TI-2026-42089 mcp-searxng: DNS-resolved Private Hostname SSRF in `web_url_read` CVSS 3.1HIGH 7.1
  • TI-2026-39509 mcp-searxng: SSRF in web_url_read: the internal-address guard is disabled by default (MCP_HTTP_HARDEN off) CVSS 3.1MEDIUM 6.5
  • TI-2026-39510 mcp-searxng hardened-mode SSRF bypasses permit internal URL access CVSS 3.1MEDIUM 6.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences