Cyber Resilience

CVE-2022-26531

MediumPublic PoC

Published: 24 May 2022

Published
24 May 2022
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 6.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H
EPSS Score 0.0099 77.3th percentile
Risk Priority 13 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2022-26531 is a medium-severity Improper Input Validation (CWE-20) vulnerability in Zyxel Nsg300 Firmware. Its CVSS base score is 6.1 (Medium).

Operationally, ranked in the top 22.7% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

zyxel
vpn100 firmware
4.30 — 5.21
zyxel
vpn1000 firmware
4.30 — 5.21
zyxel
vpn300 firmware
4.30 — 5.21
zyxel
vpn50 firmware
4.30 — 5.21
zyxel
atp100 firmware
4.32 — 5.21
zyxel
atp100w firmware
4.32 — 5.21
zyxel
atp200 firmware
4.32 — 5.21
zyxel
atp500 firmware
4.32 — 5.21
zyxel
atp700 firmware
4.32 — 5.21
zyxel
atp800 firmware
4.32 — 5.21
+55 more product configuration(s) — see NVD for full list

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

References