Vulnerability · CVE-2026-100394
Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool.
Published Oct 14, 2026 · catalog updated Oct 15, 2026 · Nezha Monitoring is a
Check if you run it
No confirmed exploitation is on record for CVE-2026-100394. EPSS is 0.42%. Act only if a listed version of Nezha Monitoring is a is installed.
Gaps on this record
- The stored product name is a package slug. The name on this page is taken from the title (Nezha Monitoring is a).
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- Medium6.5
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.42%
- Remediation
- Version ranges on file
- Affected products
- Go github.com/nezhahq/nezha · go github.com/nezhahq/nezha · golang github.com
## Summary A single low-privilege can take the entire Nezha dashboard offline, and with it every tenant's web UI, REST API, and agent connections, by racing two ordinary operations on their own service. The crash is a nil pointer dereference in the service-monitor worker at . The worker checks a service exists under one lock and later writes to two pointer-valued status maps under a different lock; a concurrent delete removes the entries in the gap. Because the gRPC server has no recovery interceptor, the worker-goroutine panic kills the whole process. Availability only: nothing is read or modified. ## Affected versions Confirmed in through . has the same vulnerable implementation in all four releases. The issue is fixed in and later; users should upgrade to the latest release, . ## The bug The worker validates an incoming report and later writes it to two status maps, but the check and the write are guarded by two different locks taken at two different times. Between them, the same member can delete the service and pull the map entries out from under the worker. The maps hold pointers, so a missing key returns nil and the first field write through it panics: The worker checks presence via , which takes and releases it. rejects a nil service here, so at this point the service is known to exist: For TCP/ICMP ping results, every (default 2, TSDB off) the worker does a synchronous at holding neither status-map lock, which stretches the gap into an easily raceable window. It then takes a *different* lock and dereferences the maps with no recheck and no lazy create: Meanwhile removes both entries under , running on the HTTP-handler goroutine, a different goroutine from the single worker: The precise point: the check reads the map under ; the write touches under . Holding the second lock at proves nothing about whether the entry survived, because the delete ran under that same lock while the worker was still busy between the two operations. This is a cross-lock TOCTOU, no
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- Go github.com/nezhahq/nezha0.0.0-20260628010923-fd31e5f1b0f8 → 0.0.0-20260721131105-c893aa57867d
- go github.com/nezhahq/nezha>= 0.0.0-20260628010923-fd31e5f1b0f8, < 0.0.0-20260721131105-c893aa57867d
- golang github.comversion unspecified
How to fix CVE-2026-100394
Recommended remediation
Affected version ranges suggest a fixed boundary. Verify against the vendor advisory for your release.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-100394. EPSS is 0.42%. Act only if a listed version of Nezha Monitoring is a is installed.
Which versions are affected?
Compare what you have installed with 0.0.0-20260628010923-fd31e5f1b0f8 → 0.0.0-20260721131105-c893aa57867d, >= 0.0.0-20260628010923-fd31e5f1b0f8, < 0.0.0-20260721131105-c893aa57867d. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
CWE-362: Race Condition; CWE-476: NULL Pointer Dereference. EPSS 0.42%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Oct 14, 2026 · NIST NVD
Detected
Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From 2.2.7 until 2.2.11, ServiceSentinel.worker in service/singleton/servicesentinel.go checked an owned service under servicesLock and later dereferenced pointer-valued serviceStatusToday and serviceCurrentStatusData entries under serviceResponseDataStoreLock without revalidating that ServiceSentinel.D
Oct 14, 2026 · NIST NVD
Updated
Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From 2.2.7 until 2.2.11, ServiceSentinel.worker in service/singleton/servicesentinel.go checked an owned service under servicesLock and later dereferenced pointer-valued serviceStatusToday and serviceCurrentStatusData entries under serviceResponseDataStoreLock without revalidating that ServiceSentinel.D
Oct 15, 2026 · GitHub Advisory Database
Fix available
github.com/nezhahq/nezha fixed in 0.0.0-20260721131105-c893aa57867d
Oct 15, 2026 · GitHub Advisory Database
Fix available
github.com/nezhahq/nezha fixed in 0.0.0-20260721131105-c893aa57867d
Oct 15, 2026 · GitHub Advisory Database
Updated
## Summary A single low-privilege can take the entire Nezha dashboard offline, and with it every tenant's web UI, REST API, and agent connections, by racing two ordinary operations on their own service. The crash is a nil pointer dereference in the service-monitor worker at . The worker checks a service exists under one lock and later writes to two pointer-valued status maps under a different lock
Sources
- CVE.orgVulnerability recordCVE-2026-100394
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-100394
30-day exploitation probability 0.4%
first.org - GitHub Advisory DatabasePackage advisoryGHSA-qjpp-gffx-2wm9
Nezha Monitoring: Whole-instance DoS in Nezha dashboard: a member can crash the process for every tenant
github.com - GitLab Advisory DatabasePackage advisoryCVE-2026-100394
A single low-privilege RoleMember can take the entire Nezha dashboard offline, and with it every tenant's web UI, REST API, and agent connections, by racing two ordinary operations on their own service. The crash is a nil pointer dereference in the service-monitor worker at service/singleton/servicesentinel.go:601. The worker checks a service exists under one lock and later writes to two pointer-v
advisories.gitlab.com - NIST NVDVulnerability recordCVE-2026-100394
Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From 2.2.7 until 2.2.11, ServiceSentinel.worker in service/singleton/servicesentinel.go checked an owned service under servicesLock and later dereferenced pointer-valued serviceStatusT
nvd.nist.gov - OpenSSF OSV / OSV ScannerPackage advisoryGHSA-qjpp-gffx-2wm9
Nezha Monitoring: Whole-instance DoS in Nezha dashboard: a member can crash the process for every tenant
osv.dev
References
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.