CVE-2026-89009 json
WAVLINK WN535M1/WN535M3 Unauthenticated Arbitrary File Write via sync_server
published 2026-09-11 58 d ago modified 2026-10-29 10 d ago also EUVD-2026-76129
- cvss
- 9.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.0%
- EPSS 1.0% chance of exploitation in 30 days, percentile 63%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- WAVLINK Technology WN535M1 M35M1_V250922
- WAVLINK Technology WN535M3 M35M1_V250922
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 54 d ago
Exploit prediction
1.01% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/camdsmith/wavlink-sync_server-rce/blob/main/README.md referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.8 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N |
| CNA | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H |
| CNA | 4.0 | 8.8 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/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 products
- WAVLINK Technology WN535M1
- WAVLINK Technology WN535M3
Classification
- Weakness
-
- CWE-36 Absolute Path Traversal
References
-
docs.wavlink.xyz
/Security_Advisory/WAVLINK-SA-2026-091301/
patch, vendor-advisory
-
github.com
/camdsmith/wavlink-sync_server-rce/blob/main/README.md
technical-description, exploit
-
vulncheck.com
/advisories/wavlink-wn535m1-wn535m3-unauthenticated-arbitrary-file-write-via-sync-server
third-party-advisory
Sources
- CVE List CVE-2026-89009
- NVD CVE-2026-89009
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