CVE-2022-30525
CVE-2022-30525 is a security flaw in Zyxel Multiple Firewalls, firewalls and routers for homes and small businesses. Attackers can run commands on Zyxel Multiple Firewalls. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 16 May 2022.[1]
Zyxel Multiple Firewalls is in things households have: home and small-office routers, so the fix matters at home as much as at work. Zyxel has published a fix or advice.
Description
CISA calls it an OS command injection in Zyxel Multiple Firewalls. In its words: “A command injection vulnerability in the CGI program of some Zyxel firewall versions could allow an attacker to modify specific files and then execute some OS commands on a vulnerable device.”[1]
The CVE record adds: “A OS command injection vulnerability in the CGI program of Zyxel USG FLEX 100(W) firmware versions 5.00 through 5.21 Patch 1, USG FLEX 200 firmware versions 5.00 through 5.21 Patch 1, USG FLEX 500 firmware versions 5.00 through 5.21 Patch 1, USG FLEX 700 firmware versions 5.00 through 5.21 Patch 1, USG FLEX 50(W) firmware versions 5.10 through 5.21 Patch 1, USG20(W)-VPN firmware versions 5.10 through 5.21 Patch 1, ATP series firmware versions 5.10 through 5.21 Patch 1, VPN series firmware versions 4.60 through 5.21 Patch 1, which could allow an attacker to modify specific files and then execute some OS commands on a vulnerable device.”[2]
The underlying weakness is OS command injection (CWE-78), in MITRE’s list of common software weaknesses.
It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Zyxel’s advisory has them[3]. CISA names the product as Zyxel Multiple Firewalls.
Every device with Zyxel Multiple Firewalls needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 16 May 2022, 4 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 6 Jun 2022 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at over 99%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Zyxel has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Update Zyxel Multiple Firewalls now.Open the router’s app, or its admin page in a browser, and look for a firmware update. Then turn on automatic updates, so the next fix arrives on its own.
- If the maker has stopped updating it, replace it.Routers stop getting fixes after a few years, and attackers keep a list of the ones that did. If there’s no newer firmware, it won’t be fixed.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at over 99%.[4] |
See also
Other Zyxel Multiple Firewalls flaws
- CVE-2024-11667: path traversal ·
- CVE-2023-33010: buffer overflow ·
- CVE-2023-33009: buffer overflow ·
- CVE-2023-28771: OS command injection ·
Other Zyxel flaws
- CVE-2026-7273, Zyxel GS1900 Series Switches: stack-based buffer overflow ·
- CVE-2024-40891, Zyxel DSL CPE Devices: DSL CPE OS command injection ·
- CVE-2024-40890, Zyxel DSL CPE Devices: DSL CPE OS command injection ·
- CVE-2017-6884, Zyxel EMG2926 Routers: command injection ·
- CVE-2017-18368, Zyxel P660HN-T1A Routers: command injection ·
Other OS command injection flaws
- CVE-2026-110447, Collabora Online – Built-in CODE Server: online – built-in CODE server OS command injection ·
- CVE-2026-106931, EG Secure Solutions SiteGuard Server Edition: OS command injection ·
- CVE-2026-83549, SonicWall SMA1000 Appliances: OS command injection ·
- CVE-2026-49869, Kestra OSS: OSS OS command injection ·
- CVE-2026-73570, Synacor Zimbra Collaboration Suite (ZCS): OS command injection ·
Added the same day
- CVE-2022-22947, VMware Spring Cloud Gateway: code injection ·
Every Zyxel flaw on CISA’s list · Everything added in May 2022
References
- ^ Cybersecurity and Infrastructure Security Agency. “Zyxel Multiple Firewalls OS Command Injection Vulnerability”. Known Exploited Vulnerabilities Catalog, added 16 May 2022.
- ^ National Institute of Standards and Technology. “CVE-2022-30525 Detail”. National Vulnerability Database, published 12 May 2022.
- ^ Zyxel. Advisories and fixes: zyxel.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.999, percentile 100.0, 31 Oct 2026.
- CVE Program. “CVE-2022-30525”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.