CVE-2022-26531Multiple improper input validation flaws were identified in some CLI commands of Zyxel USG/ZyWALL series firmware versions 4.09 through…
- 6.1MediumCVSS base score
- 6.4%Exploitation in 30 daysEPSS · top 6.2% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
Multiple improper input validation flaws were identified in some CLI commands of Zyxel USG/ZyWALL series firmware versions 4.09 through 4.71, USG FLEX series firmware versions 4.50 through 5.21, ATP series firmware versions 4.32 through 5.21, VPN series firmware versions 4.30 through 5.21, NSG series firmware versions 1.00 through 1.33 Patch 4, NXC2500 firmware version 6.10(AAIG.3) and earlier versions, NAP203 firmware version 6.25(ABFA.7) and earlier versions, NWA50AX firmware version 6.25(ABYW.5) and earlier versions, WAC500 firmware version 6.30(ABVS.2) and earlier versions, and WAX510D firmware version 6.30(ABTF.2) and earlier versions, that could allow a local authenticated attacker to cause a buffer overflow or a system crash via a crafted payload.
Timeline
ID reserved
By Zyxel
- 3 months later
· 3 months later
Published
- 2 years later
· 2 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| ZyxelCNA (assigner) | 3.1 | Medium6.1 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H |
| NVDNVD · Modified | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 6.4% · top 6.2% of all CVEs (15 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.1.
Affected products
Zyxel · USG/ZyWALL series firmware
- affected 4.09 through 4.71
Zyxel · USG FLEX series firmware
- affected 4.50 through 5.21
- affected 4.32 through 5.21
- affected 4.30 through 5.21
- affected 1.00 through 1.33 Patch 4
- affected <= 6.10(AAIG.3)
- affected <= 6.25(ABFA.7)
- affected <= 6.25(ABYW.5)
- affected <= 6.30(ABVS.2)
- affected <= 6.30(ABTF.2)
References
References4
- https://www.zyxel.com/support/multiple-vulnerabilities-of-firewalls-AP-controllers-and-APs.shtml (opens in a new tab)x_transferred
- 20220610 HNS-2022-02 - HN Security Advisory - Multiple vulnerabilities in Zyxel zysh (opens in a new tab)mailing-listx_transferred
- http://packetstormsecurity.com/files/167464/Zyxel-Buffer-Overflow-Format-String-Command-Injection.html (opens in a new tab)x_transferred
- http://packetstormsecurity.com/files/177036/Zyxel-zysh-Format-String-Proof-Of-Concept.html (opens in a new tab)x_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2022-31088 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2022-26531)Record last updated .