Vulnerability in Nezhahq Nezha
CVE-2026-101088
Nezha is a server and website monitoring tool. In versions >= 2.2.11 and < 2.3.1, the service sentinel worker (service/singleton/servicesentinel.go) contains an incomplete fix for a previously reported nil dereference denial of service (GHSA-qjpp-gffx-2wm9). The 2026-07-21 fix re-validated the service lifecycle under serviceResponseDataStoreLock but reused an already-captured, now stale reporter pointer and never re-validated the server, and that lock does not guard ServerShared. An authenticated user with the member role who owns an agent can issue a concurrent server delete (POST /api/v1/batch-delete/server) for their own server to win the race window, causing the worker to dereference a missing entry in the server list snapshot. Because the sentinel workers and the gRPC server have no recover()/recovery interceptor, the resulting panic is unrecovered and crashes the entire instance. This is fixed in version 2.3.1.
Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)
Published .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H.
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-jx78-55p5-rwv5 (vendor-advisory)
- www.vulncheck.com/advisories/nezha-before-2.3.1-denial-of-service-via-concurren… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-101088?
- CVE-2026-101088 is a medium-severity vulnerability in Nezhahq Nezha, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 5.3/10. Published 2026-09-27.
- How severe is CVE-2026-101088?
- Medium severity. CVSS v3 base score is 5.3 out of 10.