CVE-2026-89009

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreHIGH confidence

Score 9.1 from GitHub Security Advisory (severity: HIGH) published 2026-09-11. a secondary CVSS source baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.1Exploit: Elevated riskExposed: 0

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

WAVLINK WN535M1 and WN535M3 routers running firmware prior to M35M1_V250922 contain an unauthenticated arbitrary file write vulnerability that allows remote attackers to overwrite any file on the device by sending a crafted payload to the sync_server daemon on TCP port 13136. The daemon, which runs as root and requires no authentication, accepts a 100-byte filename field in its protocol header without path canonicalization, allowing attackers to supply an absolute path and write arbitrary content to overwrite startup scripts or credential stores to achieve persistent system compromise.

CVSS v3
9.1
EG Score
9.1(high)
EG Risk
72(Attend)
EG Risk 72/100SSVC: Attend

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
Severity91% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
51%
KEV
Not listed

Published

September 11, 2026

Last Modified

September 15, 2026

Advisory Details (3)

Auto-updated Sep 15, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

wavlink-sync_server-rce/README.md at main · camdsmith/wavlink-sync_server-rce · GitHub

https://github.com/camdsmith/wavlink-sync_server-rce/blob/main/README.md
generic

WAVLINK WN535M1/WN535M3 Unauthenticated Arbitrary File Write via sync_server | Advisories | VulnCheck

https://www.vulncheck.com/advisories/wavlink-wn535m1-wn535m3-unauthenticated-arbitrary-file-write-via-sync-server
generic

WAVLINK ROUTER Docs

https://docs.wavlink.xyz/

Vendor Advisories for CVE-2026-89009(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 58× in last 7d / 67× 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. 2026-09-19 08:04 UTCGHSA enrichment
  2. 2026-09-19 04:07 UTCGHSA enrichment
  3. 2026-09-19 00:10 UTCGHSA enrichment
  4. 2026-09-18 20:13 UTCEG score recompute
  5. 2026-09-18 20:13 UTCGHSA enrichment
  6. 2026-09-18 19:28 UTCEPSS rescore
  7. 2026-09-18 16:12 UTCGHSA enrichment
  8. 2026-09-18 11:44 UTCGHSA enrichment
  9. 2026-09-18 07:47 UTCGHSA enrichment
  10. 2026-09-18 03:50 UTCGHSA enrichment
  11. 2026-09-17 23:53 UTCGHSA enrichment
  12. 2026-09-17 19:42 UTCEG score recompute
  13. 2026-09-17 19:42 UTCGHSA enrichment
  14. 2026-09-17 19:32 UTCEPSS rescore
  15. 2026-09-17 14:18 UTCGHSA enrichment
  16. 2026-09-17 10:21 UTCGHSA enrichment
  17. 2026-09-17 06:23 UTCGHSA enrichment
  18. 2026-09-17 02:22 UTCGHSA enrichment
  19. 2026-09-16 22:22 UTCGHSA enrichment
  20. 2026-09-16 18:06 UTCEG score recompute
  21. 2026-09-16 18:06 UTCGHSA enrichment
  22. 2026-09-16 14:09 UTCEPSS rescore
  23. 2026-09-16 13:51 UTCGHSA enrichment
  24. 2026-09-16 09:21 UTCGHSA enrichment
  25. 2026-09-16 05:23 UTCEG score recompute
Show 42 more
  1. 2026-09-16 05:23 UTCGHSA enrichment
  2. 2026-09-16 05:15 UTCEPSS rescore
  3. 2026-09-16 01:27 UTCGHSA enrichment
  4. 2026-09-15 21:30 UTCGHSA enrichment
  5. 2026-09-15 17:33 UTCEG score recompute
  6. 2026-09-15 17:33 UTCGHSA enrichment
  7. 2026-09-15 16:35 UTCEG score recompute
  8. 2026-09-15 16:34 UTCGHSA enrichment
  9. 2026-09-15 13:03 UTCGHSA enrichment
  10. 2026-09-15 09:05 UTCGHSA enrichment
  11. 2026-09-15 05:08 UTCEG score recompute
  12. 2026-09-15 05:07 UTCGHSA enrichment
  13. 2026-09-15 03:12 UTCEPSS rescore
  14. 2026-09-15 01:07 UTCGHSA enrichment
  15. 2026-09-14 21:10 UTCGHSA enrichment
  16. 2026-09-14 16:59 UTCGHSA enrichment
  17. 2026-09-14 13:02 UTCGHSA enrichment
  18. 2026-09-14 09:05 UTCGHSA enrichment
  19. 2026-09-14 05:08 UTCGHSA enrichment
  20. 2026-09-14 01:11 UTCGHSA enrichment
  21. 2026-09-13 21:14 UTCGHSA enrichment
  22. 2026-09-13 17:17 UTCEG score recompute
  23. 2026-09-13 17:17 UTCGHSA enrichment
  24. 2026-09-13 16:48 UTCEPSS rescore
  25. 2026-09-13 13:20 UTCGHSA enrichment
  26. 2026-09-13 09:23 UTCGHSA enrichment
  27. 2026-09-13 05:26 UTCGHSA enrichment
  28. 2026-09-13 01:29 UTCGHSA enrichment
  29. 2026-09-12 21:32 UTCGHSA enrichment
  30. 2026-09-12 17:35 UTCEG score recompute
  31. 2026-09-12 17:35 UTCGHSA enrichment
  32. 2026-09-12 15:02 UTCEPSS rescore
  33. 2026-09-12 13:38 UTCGHSA enrichment
  34. 2026-09-12 09:41 UTCGHSA enrichment
  35. 2026-09-12 05:44 UTCGHSA enrichment
  36. 2026-09-12 01:47 UTCGHSA enrichment
  37. 2026-09-11 21:50 UTCGHSA enrichment
  38. 2026-09-11 17:53 UTCEG score recompute
  39. 2026-09-11 17:53 UTCGHSA enrichment
  40. 2026-09-11 15:28 UTCEG score recompute
  41. 2026-09-11 15:04 UTCEG score recompute
  42. 2026-09-11 15:03 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-89009?
CVE-2026-89009 is a critical vulnerability published on September 11, 2026. WAVLINK WN535M1 and WN535M3 routers running firmware prior to M35M1V250922 contain an unauthenticated arbitrary file write vulnerability that allows remote attackers to overwrite any file on the device by sending a crafted payload to the syncserver daemon on TCP port 13136. The daemon, which runs…
When was CVE-2026-89009 disclosed?
CVE-2026-89009 was first published in the National Vulnerability Database on September 11, 2026, with the most recent update on September 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-89009 actively exploited?
CVE-2026-89009 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 49.2% of all scored CVEs.
What is the CVSS score of CVE-2026-89009?
CVE-2026-89009 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-89009?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-89009, 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

Explore the affected products and dependency analysis for CVE-2026-89009

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