CVE-2026-43981

HIGHPre-NVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.2 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 92% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cna:github_m, epss
Trending — 3 sources updated this week
8.2
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.2Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
8.2
EG Score
8.2(medium)
EG Risk
37(Track)
EG Risk 37/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity82% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
8.1%
KEV
Not listed

Published

May 26, 2026

Last Modified

July 24, 2026

Advisory Details (2)

Auto-updated Jun 2, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic🟡 PoC Available

Security Vulnerabilities – Responsible Disclosure · Issue #172 · xyproto/algernon · GitHub

https://github.com/xyproto/algernon/issues/172
github Patch Available

Race Condition in handle() shared LState · Advisory · xyproto/algernon · GitHub

Affected: version 1.17.6.

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

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 32× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-24 14:17 UTCEPSS rescore
  2. 2026-07-23 14:18 UTCEPSS rescore
  3. 2026-07-23 03:14 UTCEG score recompute
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  7. 2026-07-19 14:31 UTCEPSS rescore
  8. 2026-07-19 06:22 UTCOSV refresh
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  1. 2026-06-30 23:22 UTCEPSS rescore
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  5. 2026-06-27 03:08 UTCEPSS rescore
  6. 2026-06-25 13:49 UTCEPSS rescore
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  8. 2026-06-24 14:05 UTCEPSS rescore
  9. 2026-06-23 21:33 UTCEPSS rescore
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  20. 2026-06-15 17:49 UTCEPSS rescore
  21. 2026-06-13 23:00 UTCEPSS rescore
  22. 2026-06-12 23:12 UTCEPSS rescore
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  24. 2026-06-11 14:00 UTCEPSS rescore
  25. 2026-06-10 22:18 UTCEPSS rescore
  26. 2026-06-10 13:22 UTCEPSS rescore
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  28. 2026-06-08 14:17 UTCEPSS rescore
  29. 2026-06-08 14:17 UTCEPSS rescore
  30. 2026-06-07 15:25 UTCEPSS rescore
  31. 2026-06-07 15:25 UTCEPSS rescore
  32. 2026-06-06 13:47 UTCEPSS rescore
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  35. 2026-06-05 06:10 UTCEPSS rescore
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  37. 2026-06-04 13:12 UTCEPSS rescore
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  39. 2026-06-01 13:52 UTCEPSS rescore
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  41. 2026-05-31 22:30 UTCEPSS rescore
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  43. 2026-05-31 00:16 UTCEPSS rescore
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  45. 2026-05-29 13:44 UTCEPSS rescore
  46. 2026-05-29 13:44 UTCEPSS rescore
  47. 2026-05-28 13:44 UTCEPSS rescore
  48. 2026-05-28 13:44 UTCEPSS rescore
  49. 2026-05-27 13:40 UTCEPSS rescore
  50. 2026-05-27 13:40 UTCEPSS rescore
  51. 2026-05-26 17:02 UTCEG score recompute

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Frequently asked(5)

What is CVE-2026-43981?
CVE-2026-43981 is a high vulnerability published on May 26, 2026. 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…
When was CVE-2026-43981 disclosed?
CVE-2026-43981 was first published in the National Vulnerability Database on May 26, 2026, with the most recent update on July 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-43981 actively exploited?
CVE-2026-43981 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 8.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-43981?
CVE-2026-43981 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-43981?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-43981, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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