HOMEVULNERABILITIESCVE-2026-43981
HIGH

CVE-2026-43981

CWE-362Published: May 26, 2026· Updated: May 26, 2026

8.2
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2026-43981 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityHigh
Privileges Req.None
User InteractionNone
ScopeX
Impact
Confidentiality
Integrity
Availability
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

Affected Vendors & Products

Mentioned vendors (from description):
Go
CPE data not yet available in NVD for this CVE.

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
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All References (2)

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

Quick Facts

CVE IDCVE-2026-43981
CVSS Score8.2 / 10
SeverityHIGH
WeaknessCWE-362
CISA KEVNo
PublishedMay 26, 2026

Related CVEs (CWE-362)

CVE-2026-5902
9.8
CVE-2025-13036
9.2
CVE-2025-10263
9.1
CVE-2026-20677
9.0
CVE-2025-32991
9.0
CVE-2026-44693
8.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2026-43981 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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