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.
{
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43981.json",
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-362"
]
}