{"id":"CVE-2026-43981","state":"PUBLISHED","title":"Algernon: Race Condition in handle() shared LState","description":"Algernon is a small self-contained pure-Go web server. Prior to 1.17.6, in engine/luahandler.go, the sync.RWMutex protecting LoadCommonFunctions is released before L.Push() and L.PCall() execute. Since gopher-lua's LState is explicitly not goroutine-safe, concurrent requests race on the shared state causing Lua VM corruption. The Go race detector confirms this immediately under modest concurrency (ab -n 1000 -c 100). This vulnerability is fixed in 1.17.6.","publishedAt":"2026-05-26T16:31:55.696Z","updatedAt":"2026-05-27T13:47:52.116Z","severity":{"score":8.2,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["xyproto algernon"],"affected":[{"vendor":"xyproto","product":"algernon","versions":[{"version":"< 1.17.6","status":"affected"}]}],"references":["https://github.com/xyproto/algernon/security/advisories/GHSA-rr2f-4wrm-h6rg","https://github.com/xyproto/algernon/issues/172"],"weaknesses":["CWE-362"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/43xxx/CVE-2026-43981.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-43981","state":"PUBLISHED","datePublished":"2026-05-26T16:31:55.696Z","dateUpdated":"2026-05-27T13:47:52.116Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-04T20:24:31.916Z"},"containers":{"cna":{"title":"Algernon: Race Condition in handle() shared LState","descriptions":[{"lang":"en","value":"Algernon is a small self-contained pure-Go web server. Prior to 1.17.6, in engine/luahandler.go, the sync.RWMutex protecting LoadCommonFunctions is released before L.Push() and L.PCall() execute. Since gopher-lua's LState is explicitly not goroutine-safe, concurrent requests race on the shared state causing Lua VM corruption. The Go race detector confirms this immediately under modest concurrency (ab -n 1000 -c 100). This vulnerability is fixed in 1.17.6."}],"affected":[{"vendor":"xyproto","product":"algernon","versions":[{"version":"< 1.17.6","status":"affected"}]}],"references":[{"url":"https://github.com/xyproto/algernon/security/advisories/GHSA-rr2f-4wrm-h6rg","name":"https://github.com/xyproto/algernon/security/advisories/GHSA-rr2f-4wrm-h6rg","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/xyproto/algernon/issues/172","name":"https://github.com/xyproto/algernon/issues/172","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.2,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-362","lang":"en","description":"CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-05-26T16:31:55.696Z"},"source":{"advisory":"GHSA-rr2f-4wrm-h6rg","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-27T13:46:42.476250Z","id":"CVE-2026-43981","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-27T13:47:52.116Z"}}]}}}