CVE-2023-22917

CVE-2023-22917 is a high-severity vulnerability in Zyxel Usg Flex 100 Firmware with a CVSS 3.x base score of 7.5. 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-120.

Key facts

• Severity: High (CVSS 3.x base score 7.5)
• EPSS exploit prediction: 1% (55th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-120
• Affected product: Zyxel Usg Flex 100 Firmware
• Published: 2023-04-24
• Last modified: 2026-06-17

Description

A buffer overflow vulnerability in the “sdwan_iface_ipc” binary of Zyxel ATP series firmware versions 5.10 through 5.32, USG FLEX series firmware versions 5.00 through 5.32, USG FLEX 50(W) firmware versions 5.10 through 5.32, USG20(W)-VPN firmware versions 5.10 through 5.32, and VPN series firmware versions 5.00 through 5.35, which could allow a remote unauthenticated attacker to cause a core dump with a request error message on a vulnerable device by uploading a crafted configuration file.

Frequently asked questions

What is CVE-2023-22917?

A buffer overflow vulnerability in the “sdwan_iface_ipc” binary of Zyxel ATP series firmware versions 5.10 through 5.32, USG FLEX series firmware versions 5.00 through 5.32, USG FLEX 50(W) firmware versions 5.10 through 5.32, USG20(W)-VPN firmware versions 5.10 through 5.32, and VPN series firmware versions 5.00 through 5.35, which could allow a remote unauthenticated attacker to cause a core dump with a request error message on a vulnerable device by uploading a crafted configuration file.

How severe is CVE-2023-22917?

CVE-2023-22917 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2023-22917 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-22917?

CVE-2023-22917 primarily affects Zyxel Usg Flex 100 Firmware. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-22917?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2023-22917 published?

CVE-2023-22917 was published on 2023-04-24 and last updated on 2026-06-17.

References

• https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-of-firewalls-and-aps

Affected products (18)

• 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_50_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:zyxel:usg_flex_50w_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:zyxel:usg_flex_500_firmware:*:*:*:*:*:*:*:*
• cpe:2.3:o:zyxel:usg_flex_700_firmware:*:*:*:*:*:*:*:*
• 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:usg_20w-vpn_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:*:*:*:*:*:*:*:*

More vulnerabilities in Zyxel Usg Flex 100 Firmware

• CVE-2023-33010 — Critical (CVSS 9.8): A buffer overflow vulnerability in the ID processing function in Zyxel ATP series firmware versions 4.32 through 5.36…
• CVE-2023-33009 — Critical (CVSS 9.8): A buffer overflow vulnerability in the notification function in Zyxel ATP series firmware versions 4.60 through 5.36…
• CVE-2023-28771 — Critical (CVSS 9.8): Improper error message handling in Zyxel ZyWALL/USG series firmware versions 4.60 through 4.73, VPN series firmware…
• CVE-2022-0342 — Critical (CVSS 9.8): An authentication bypass vulnerability in the CGI program of Zyxel USG/ZyWALL series firmware versions 4.20 through…
• CVE-2021-35029 — Critical (CVSS 9.8): An authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall series firmware…
• CVE-2020-29583 — Critical (CVSS 9.8): Firmware version 4.60 of Zyxel USG devices contains an undocumented account (zyfwp) with an unchangeable password. The…

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