Nezha before 2.3.1 Denial of Service via Concurrent Server Delete
Summary
| CVE | CVE-2026-101088 |
|---|---|
| State | PUBLISHED |
| Assigner | VulnCheck |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-27 21:17:02 UTC |
| Updated | 2026-09-27 21:17:02 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 6 MEDIUM from [email protected]
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
Problem Types: CWE-367 | CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 6 | MEDIUM | 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/C... |
| 4.0 | CNA | CVSS | 6 | MEDIUM | 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 |
| 3.1 | [email protected] | Primary | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | CVSS | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
HighAttack Requirements
PresentPrivileges Required
LowUser Interaction
NoneConfidentiality
NoneIntegrity
NoneAvailability
HighSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS: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
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
NoneAvailability
HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/nezhahq/nezha/security/advisories/GHSA-jx78-55p5-rwv5 | [email protected] | github.com | |
| www.vulncheck.com/advisories/nezha-before-2.3.1-denial-of-service-via-concurren... | [email protected] | www.vulncheck.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: arpitjain099 (en)
There are currently no legacy QID mappings associated with this CVE.