CVE-2026-43981 Details
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.
A race condition vulnerability has been identified in Algernon versions prior to 1.17.6. The issue arises in the Lua handler, where the synchronization mutex is released before executing Lua function calls. This flaw creates a concurrency issue, as the Lua state is not safe for simultaneous operations, leading to corruption of the Lua virtual machine. The vulnerability can be reproduced under moderate load, causing a denial-of-service condition when using Lua with Algernon.
Users can update to Algernon version 1.17.6 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed May 26, 2026CISA-ADP
Assessed May 27, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/xyproto/algernon/issues/172 | [email protected] | BundleExploitIssue TrackingTechnical DescriptionVendor |
| https://github.com/xyproto/algernon/security/advisories/GHSA-rr2f-4wrm-h6rg | [email protected] | AdvisoryRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-362 | Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Algernon | < 1.17.6 (semver) |
CPE
Remediation
| |
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 24, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 26, 2026 | New CVE Received | [email protected] |