Nezha before 2.3.1 Denial of Service via Concurrent Server Delete (nezhahq nezha)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.18 % · percentile 8 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- VulnCheck
- NVD status
- Deferred
Description
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.
Weaknesses (CWE)
- CWE-367 — Time-of-check Time-of-use (TOCTOU) Race Condition
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | MEDIUM 6.0 | CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H | VulnCheck |
| CVSS 4.0 | MEDIUM 6.0 | CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · disclosure@vulncheck.com (Secondary) |
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H | NVD · disclosure@vulncheck.com (Secondary) |
European references
- ENISA EUVD · EUVD-2026-88023
- GCVE · GCVE-0-2026-101088
Affected products
| Product | Versions |
|---|---|
| nezhahq · nezha | affected 2.2.11 < 2.3.1 ; unaffected 2.3.1 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |