How severe is CVE-2023-6397?

CVE-2023-6397 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2023-6397 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-6397?

CVE-2023-6397 primarily affects Zyxel Atp100 Firmware. In total, 57 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-6397?

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

Does CVE-2023-6397 have an EU (EUVD) identifier?

Yes. CVE-2023-6397 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-58634.

When was CVE-2023-6397 published?

CVE-2023-6397 was published on 2024-02-20 and last updated on 2026-06-17.

CVE-2023-6397

CVE-2023-6397 is a medium-severity vulnerability in Zyxel Atp100 Firmware with a CVSS 3.x base score of 6.5. 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-476.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (22nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2023-58634
Weakness: CWE-476
Affected product: Zyxel Atp100 Firmware
Published: 2024-02-20
Last modified: 2026-06-17

Description

A null pointer dereference vulnerability in Zyxel ATP series firmware versions from 4.32 through 5.37 Patch 1 and USG FLEX series firmware versions from 4.50 through 5.37 Patch 1 could allow a LAN-based attacker to cause denial-of-service (DoS) conditions by downloading a crafted RAR compressed file onto a LAN-side host if the firewall has the “Anti-Malware” feature enabled.

Frequently asked questions

What is CVE-2023-6397?: A null pointer dereference vulnerability in Zyxel ATP series firmware versions from 4.32 through 5.37 Patch 1 and USG FLEX series firmware versions from 4.50 through 5.37 Patch 1 could allow a LAN-based attacker to cause denial-of-service (DoS) conditions by downloading a crafted RAR compressed file onto a LAN-side host if the firewall has the “Anti-Malware” feature enabled.
How severe is CVE-2023-6397?: CVE-2023-6397 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2023-6397 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-6397?: CVE-2023-6397 primarily affects Zyxel Atp100 Firmware. In total, 57 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-6397?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2023-6397 have an EU (EUVD) identifier?: Yes. CVE-2023-6397 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-58634.
When was CVE-2023-6397 published?: CVE-2023-6397 was published on 2024-02-20 and last updated on 2026-06-17.

References

https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-aps-02-20-2024

Affected products (57)

cpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100w_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100w_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp200_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp200_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp500_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp500_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp700_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp700_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp700_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp800_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp800_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp800_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100ax_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100ax_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100ax_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100h_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100h_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100h_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100w_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100w_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200h_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200h_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200h_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200hp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200hp_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200hp_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_50_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Zyxel Atp100 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-2022-30525 — Critical (CVSS 9.8): A OS command injection vulnerability in the CGI program of Zyxel USG FLEX 100(W) firmware versions 5.00 through 5.21…
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-2020-29583 — Critical (CVSS 9.8): Firmware version 4.60 of Zyxel USG devices contains an undocumented account (zyfwp) with an unchangeable password. The…

All CVEs affecting Zyxel Atp100 Firmware →

Other CWE-476 (NULL Pointer Dereference) vulnerabilities

CVE-2022-36648 — Critical (CVSS 10.0): The hardware emulation in the of_dpa_cmd_add_l2_flood of rocker device model in QEMU, as used in 7.0.0 and earlier,…
CVE-2020-14500 — Critical (CVSS 10.0): Secomea GateManager all versions prior to 9.2c, An attacker can send a negative value and overwrite arbitrary data.
CVE-2010-2495 — Critical (CVSS 10.0): The pppol2tp_xmit function in drivers/net/pppol2tp.c in the L2TP implementation in the Linux kernel before 2.6.34 does…
CVE-2026-46195 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: validate dacloffset before building…
CVE-2026-31657 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: batman-adv: hold claim backbone gateways by…
CVE-2026-31436 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: fix possible wrong descriptor…

Browse all CWE-476 (NULL Pointer Dereference) vulnerabilities →