ATP series firmware: NULL Pointer Dereference
CVE-2024-42058 is a high-severity NULL pointer dereference vulnerability in ATP series firmware from Zyxel, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected ATP series firmware versions: versions V4.32 through V5.38. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.62% chance of exploitation within 30 days, higher than 50% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Zld to 5.39 or a later version.
- Read the advisory on zyxel.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Zyxel | ATP series firmware | versions V4.32 through V5.38 | Not stated |
| Zyxel | USG FLEX series firmware | versions V4.50 through V5.38 | Not stated |
| Zyxel | USG FLEX 50(W) series firmware | versions V5.20 through V5.38 | Not stated |
| Zyxel | USG20(W)-VPN series firmware | versions V5.20 through V5.38 | Not stated |
| Zyxel | atp800_firmware | 4.32 through 5.38 | Not stated |
| Zyxel | usg_flex_700h_firmware | 4.5 through 5.38 | Not stated |
| Zyxel | usg_flex_50w_firmware | 5.20 through 5.38 | Not stated |
| Zyxel | Zld | 4.32 up to, but not including, 5.39; 4.50 up to, but not including, 5.39; 4.20 up to, but not including, 5.39 | 5.39 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (zyxel.com.tw).
Official description
A null pointer dereference vulnerability in Zyxel ATP series firmware versions from V4.32 through V5.38, USG FLEX series firmware versions from V4.50 through V5.38, USG FLEX 50(W) series firmware versions from V5.20 through V5.38, and USG20(W)-VPN series firmware versions from V5.20 through V5.38 could allow an unauthenticated attacker to cause DoS conditions by sending crafted packets to a vulnerable device.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: NULL Pointer Dereference
The product dereferences a pointer that it expects to be valid but is NULL.
How developers prevent this class of flaw
- For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
- Select a programming language that is not susceptible to these issues.
- Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in ATP series firmware
- 7.2 High severity
- 7.2 High severity
- 8.1 High severity
- 7.2 High severity
- 9.8 Critical severity
Zyxel Multiple Firewalls Path Traversal Exploited
- 7.2 High severity
Recent NULL Pointer Dereference vulnerabilities
- 8.6 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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