Vulnerability record · CVE-2026-43981 · published 26 May 2026

CVE-2026-43981: Race condition vulnerability

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.

8.2 CVSS 4.0 High EPSS 0.28% · top 81.5% CWE-362 · Race condition Deferred

8.2CVSS 4.0 base score

0.28%EPSS exploitation probability, 30 days

NoNot in CISA KEV

0Affected product versions listed by NVD

2References

24 Jul 2026Last modified by NVD

Description

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:

References

Link	Tags
https://github.com/xyproto/algernon/issues/172
https://github.com/xyproto/algernon/security/advisories/GHSA-rr2f-4wrm-h6rg

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Source: NIST National Vulnerability Database (record CVE-2026-43981), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.