SSRF in Nezhahq Nezha
CVE-2026-101087
Nezha versions 2.0.10 through 2.3.2 use a restricted HTTP client to validate user-configurable notification and DDNS webhook URLs, but the denylist did not cover IPv6 transition ranges — specifically the 6to4 prefix 2002::/16 and the local-use IPv4/IPv6 translation prefix 64:ff9b:1::/48. Because such addresses satisfy Go's netip.Addr.IsGlobalUnicast check, the URL validator accepted them. An authenticated user able to configure a webhook may be able to cause the dashboard to issue requests to an otherwise restricted IPv6 endpoint, but only where the dashboard's network provides unusual or non-standards-compliant routing for these transition ranges; no direct path to an IPv4 metadata, loopback, or private-network HTTP request has been demonstrated. The issue is fixed in version 2.3.3 (commit d1fcde8e), which blocks both prefixes.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/nezhahq/nezha/security/advisories/GHSA-jr2j-7hvh-h4q9 (vendor-advisory)
- github.com/nezhahq/nezha/commit/d1fcde8e (patch)
- www.vulncheck.com/advisories/nezha-2.0.10-through-2.3.2-ssrf-denylist-bypass-ip… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-101087?
- CVE-2026-101087 is a medium-severity vulnerability in Nezhahq Nezha, classified under Server-Side Request Forgery (SSRF). CVSS score: 4.3/10. Published 2026-09-27.
- How severe is CVE-2026-101087?
- Medium severity. CVSS v3 base score is 4.3 out of 10.