xyproto algernon up to 1.17.5 engine/luahandler.go L.Push race condition

CVSS Meta Temp Score
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CTI Interest Score
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3.6$0-$5k0.00

Summaryinfo

A vulnerability identified as problematic has been detected in xyproto algernon up to 1.17.5. Affected by this vulnerability is the function L.Push of the file engine/luahandler.go. The manipulation leads to race condition. This vulnerability is uniquely identified as CVE-2026-43981. The attack is possible to be carried out remotely. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in xyproto algernon up to 1.17.5. This issue affects the function L.Push of the file engine/luahandler.go. The manipulation with an unknown input leads to a race condition vulnerability. Using CWE to declare the problem leads to CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. Impacted is availability. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-43981 since 05/04/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available.

Upgrading to version 1.17.6 eliminates this vulnerability.

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Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 3.7
VulDB Meta Temp Score: 3.6

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Race condition
CWE: CWE-362
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: algernon 1.17.6

Timelineinfo

05/04/2026 CVE reserved
05/26/2026 +22 days Advisory disclosed
05/26/2026 +0 days VulDB entry created
05/26/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: 172
Status: Confirmed

CVE: CVE-2026-43981 (🔒)
GCVE (CVE): GCVE-0-2026-43981
GCVE (VulDB): GCVE-100-365717

Entryinfo

Created: 05/26/2026 19:42
Changes: 05/26/2026 19:42 (68)
Complete: 🔍
Cache ID: 216::103

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