CVE-2026-89040

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-15. a secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: None knownExposed: 0

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

Tencent Mass Service Engine in Cluster (MSEC) allows a remote, unauthenticated attacker to send a crafted POST request including ../ and gain root access on the target device. An attacker who uploads a webshell can execute arbitrary code as root.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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
Severity98% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
59%
KEV
Not listed

Published

September 15, 2026

Last Modified

September 18, 2026

Advisory Details (2)

Auto-updated Sep 18, 2026
No patch confirmed yet.
generic
https://www.cve.org/CVERecord?id=CVE-2026-89040
generic

GitHub - Tencent/MSEC: Mass Service Engine in Cluster(MSEC) is opened source by QQ team from Tencent. It is a backend DEV &OPS engine, including RPC,name finding,load balance,monitoring,release and capacity management. · GitHub

https://github.com/Tencent/MSEC

Vendor Advisories for CVE-2026-89040(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 33× in last 7d / 33× 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. 2026-09-20 02:40 UTCGHSA enrichment
  2. 2026-09-19 22:16 UTCGHSA enrichment
  3. 2026-09-19 17:51 UTCEG score recompute
  4. 2026-09-19 17:51 UTCGHSA enrichment
  5. 2026-09-19 13:26 UTCGHSA enrichment
  6. 2026-09-19 09:01 UTCGHSA enrichment
  7. 2026-09-19 04:37 UTCGHSA enrichment
  8. 2026-09-19 00:12 UTCGHSA enrichment
  9. 2026-09-18 19:48 UTCEG score recompute
  10. 2026-09-18 19:48 UTCGHSA enrichment
  11. 2026-09-18 19:28 UTCEPSS rescore
  12. 2026-09-18 17:23 UTCGHSA enrichment
  13. 2026-09-18 12:59 UTCGHSA enrichment
  14. 2026-09-18 08:35 UTCGHSA enrichment
  15. 2026-09-18 04:11 UTCGHSA enrichment
  16. 2026-09-17 23:46 UTCEG score recompute
  17. 2026-09-17 23:46 UTCGHSA enrichment
  18. 2026-09-17 19:32 UTCEPSS rescore
  19. 2026-09-17 18:25 UTCGHSA enrichment
  20. 2026-09-17 12:06 UTCGHSA enrichment
  21. 2026-09-17 07:42 UTCGHSA enrichment
  22. 2026-09-17 03:17 UTCGHSA enrichment
  23. 2026-09-16 22:52 UTCGHSA enrichment
  24. 2026-09-16 18:27 UTCEG score recompute
  25. 2026-09-16 18:27 UTCGHSA enrichment
Show 8 more
  1. 2026-09-16 14:09 UTCEPSS rescore
  2. 2026-09-16 14:02 UTCGHSA enrichment
  3. 2026-09-16 09:38 UTCGHSA enrichment
  4. 2026-09-16 05:13 UTCGHSA enrichment
  5. 2026-09-16 00:49 UTCEG score recompute
  6. 2026-09-16 00:49 UTCGHSA enrichment
  7. 2026-09-15 20:25 UTCEG score recompute
  8. 2026-09-15 20:19 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-89040?
CVE-2026-89040 is a critical vulnerability published on September 15, 2026. Tencent Mass Service Engine in Cluster (MSEC) allows a remote, unauthenticated attacker to send a crafted POST request including ../ and gain root access on the target device. An attacker who uploads a webshell can execute arbitrary code as root.
When was CVE-2026-89040 disclosed?
CVE-2026-89040 was first published in the National Vulnerability Database on September 15, 2026, with the most recent update on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-89040 actively exploited?
CVE-2026-89040 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 40.9% of all scored CVEs.
What is the CVSS score of CVE-2026-89040?
CVE-2026-89040 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-89040?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-89040, 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.

Dependency Blast Radius

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