{"id":"CVE-2026-43981","aliases":["EUVD-2026-31866","GHSA-rr2f-4wrm-h6rg"],"status":"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.","severity":{"version":"4.0","score":8.2,"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00182,"percentile":0.07914,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-362"],"published":"2026-05-26T16:31:55Z","modified":"2026-10-28T02:31:13Z","products":[{"vendor":"xyproto","product":"algernon"}],"references":[{"url":"https://github.com/xyproto/algernon/security/advisories/GHSA-rr2f-4wrm-h6rg","tags":["x_refsource_CONFIRM","advisory"]},{"url":"https://github.com/xyproto/algernon/issues/172","tags":["x_refsource_MISC","report"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43981.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43981","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-43981","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.","status":"published","published":"2026-05-26T16:31:55.696Z","modified":"2026-05-27T13:47:52.116Z","cvss":[{"version":"4.0","score":8.2,"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","level":"high","assessor":"cna"}],"cwes":["CWE-362"],"updated_at":"2026-11-02T13:37:25.103021Z"}],"euvd":[{"id":"EUVD-2026-31866","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.","status":"published","published":"2026-05-26T16:31:55Z","modified":"2026-05-27T13:47:52Z","cvss":[{"version":"4.0","score":8.2,"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","level":"high"}],"updated_at":"2026-11-02T18:21:04.78276Z"}],"nvd":[{"id":"CVE-2026-43981","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.","status":"published","published":"2026-05-26T17:16:45.95Z","modified":"2026-07-24T11:10:00.17Z","cvss":[{"version":"4.0","score":8.2,"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/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","level":"high","assessor":"secondary"}],"cwes":["CWE-362"],"updated_at":"2026-11-02T14:12:20.131508Z"}],"osv":[{"id":"CVE-2026-43981","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.","status":"published","published":"2026-05-26T16:31:55.696Z","modified":"2026-10-28T02:31:13.947267607Z","cvss":[{"version":"4.0","score":8.2,"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","level":"high"}],"cwes":["CWE-362"],"updated_at":"2026-11-02T15:45:04.820169Z"}]}}