How severe is CVE-2022-26531?

CVE-2022-26531 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability high.

Is CVE-2022-26531 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2022-26531?

CVE-2022-26531 primarily affects Zyxel Vpn100 Firmware. In total, 80 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2022-26531?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2022-26531 published?

CVE-2022-26531 was published on 2022-05-24 and last updated on 2026-06-17.

CVE-2022-26531

CVE-2022-26531 is a medium-severity vulnerability in Zyxel Vpn100 Firmware with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.6
EPSS exploit prediction: 6% (92nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Zyxel Vpn100 Firmware
Published: 2022-05-24
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2022-26531?: 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.
How severe is CVE-2022-26531?: CVE-2022-26531 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability high.
Is CVE-2022-26531 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-26531?: CVE-2022-26531 primarily affects Zyxel Vpn100 Firmware. In total, 80 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2022-26531?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2022-26531 published?: CVE-2022-26531 was published on 2022-05-24 and last updated on 2026-06-17.

References

Affected products (80)

cpe:2.3:o:zyxel:vpn100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vpn1000_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vpn300_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vpn50_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp700_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp800_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_110_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_1100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_1900_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_20w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_20w-vpn_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_2200-vpn_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_310_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_40_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_40w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_60_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_60w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_500_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_700_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg20_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg210_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg2200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg300_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg310_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:nsg300_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:nsg300_firmware:1.33:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:nsg300_firmware:1.33:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:nsg300_firmware:1.33:patch2:*:*:*:*:*:*
cpe:2.3:o:zyxel:nsg300_firmware:1.33:patch3:*:*:*:*:*:*
cpe:2.3:o:zyxel:nsg300_firmware:1.33:patch4:*:*:*:*:*:*
cpe:2.3:o:zyxel:nsg100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:nsg100_firmware:1.33:-:*:*:*:*:*:*

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