Vulnerability · Published Apr 17, 2026 · Assigned by VulnCheck

CVE-2026-40516OpenHarness SSRF via web_fetch and web_search

High 8.3

In plain English

A high-severity server-side request forgery in OpenHarness from HKUDS. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities).

Severity (CVSS 3.1)8.3High

Exploit odds (30 days)0.2%top 92.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

OpenHarness before commit bd4df81 contains a server-side request forgery vulnerability in the web_fetch and web_search tools that allows attackers to access private and localhost HTTP services by manipulating tool parameters without proper validation of target addresses. Attackers can influence an agent session to invoke these tools against loopback, RFC1918, link-local, or other non-public addresses to read response bodies from local development services, cloud metadata endpoints, admin panels, or other private HTTP services reachable from the victim host.

Affected products (as reported)

Vendor	Product	Versions
HKUDS	OpenHarness	0 – before bd4df81f634f8c7cddcc3fdf7f561a13dcbf03ae

Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

References

https://github.com/HKUDS/OpenHarness/pull/92 issue-tracking
https://github.com/HKUDS/OpenHarness/commit/bd4df81f634f8c7cddcc3fdf7f561a13dcbf03ae patch
https://www.vulncheck.com/advisories/openharness-ssrf-via-web-fetch-and-web-search third-party-advisory