CVE-2023-35136: zyxel atp series firmware Improper Input Validation
Vulnerability summary
CVE-2023-35136 is a medium (CVSS 5.5) Improper Input Validation vulnerability in zyxel atp series firmware. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 14.5% of scored vulnerabilities.
Timeline
- 28-11-2023PublishedVulnerability first disclosed.
- 05-06-2025Last modifiedVulnerability information updated.
Description
An improper input validation vulnerability in the “Quagga” package of the Zyxel ATP series firmware versions 4.32 through 5.37, USG FLEX series firmware versions 4.50 through 5.37, USG FLEX 50(W) series firmware versions 4.16 through 5.37, USG20(W)-VPN series firmware versions 4.16 through 5.37, and VPN series firmware versions 4.30 through 5.37, could allow an authenticated local attacker to access configuration files on an affected device.
CVSS metrics
2 scores · 2 sources · 1 version- NVDNIST5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
EPSS trend
Probability
0.24%
Chance of exploitation in the next 30 days
Percentile
15%
Versus all other CVEs
30-day change
0.00 pp
From 0.24% on 20-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Zyxel6 products
- atp series firmwareversions 4.32 through 5.37
- usg flex 50(w) series firmwareversions 4.16 through 5.37
- usg flex series firmwareversions 4.50 through 5.37
- usg20(w)-vpn series firmwareversions 4.16 through 5.37
- vpn series firmwareversions 4.30 through 5.37
1 vendor · 6 products
References
1 links- www.zyxel.com/global/…Vendor Advisory