{"id":"CVE-2026-101088","state":"PUBLISHED","title":"Nezha before 2.3.1 Denial of Service via Concurrent Server Delete","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.","publishedAt":"2026-09-27T20:49:59.487Z","updatedAt":"2026-09-30T22:13:47.785Z","severity":{"score":6,"label":"Medium","version":"4.0","vector":"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","source":"VulnCheck"},"assigner":"VulnCheck","products":["nezhahq nezha"],"affected":[{"vendor":"nezhahq","product":"nezha","packageURL":"pkg:golang/github.com/nezhahq/nezha","defaultStatus":"unaffected","versions":[{"version":"2.2.11","status":"affected","lessThan":"2.3.1","versionType":"semver"},{"version":"2.3.1","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/nezhahq/nezha/security/advisories/GHSA-jx78-55p5-rwv5","https://www.vulncheck.com/advisories/nezha-before-2.3.1-denial-of-service-via-concurrent-server-delete"],"weaknesses":["CWE-367"],"ingestedAt":"2026-10-29T20:10:13.529Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/101xxx/CVE-2026-101088.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-101088","state":"PUBLISHED","datePublished":"2026-09-27T20:49:59.487Z","dateUpdated":"2026-09-30T22:13:47.785Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-09-27T20:29:07.432Z"},"containers":{"cna":{"title":"Nezha before 2.3.1 Denial of Service via Concurrent Server Delete","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"nezhahq","product":"nezha","packageURL":"pkg:golang/github.com/nezhahq/nezha","defaultStatus":"unaffected","versions":[{"version":"2.2.11","status":"affected","lessThan":"2.3.1","versionType":"semver"},{"version":"2.3.1","status":"unaffected","versionType":"semver"}]}],"references":[{"url":"https://github.com/nezhahq/nezha/security/advisories/GHSA-jx78-55p5-rwv5","tags":["vendor-advisory"],"name":"GitHub Security Advisory (GHSA-jx78-55p5-rwv5)"},{"url":"https://www.vulncheck.com/advisories/nezha-before-2.3.1-denial-of-service-via-concurrent-server-delete","name":"VulnCheck Advisory: Nezha before 2.3.1 Denial of Service via Concurrent Server Delete","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"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","attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"PRESENT","privilegesRequired":"LOW","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6,"baseSeverity":"MEDIUM"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH","baseScore":5.3,"baseSeverity":"MEDIUM"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-367","lang":"en","description":"Time-of-check Time-of-use (TOCTOU) Race Condition","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-09-27T20:49:59.487Z"},"datePublic":"2026-08-01T00:00:00.000Z","credits":[{"lang":"en","value":"arpitjain099","type":"reporter"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-30T22:13:38.135868Z","id":"CVE-2026-101088","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-30T22:13:47.785Z"}}]}}}