WRT54GL Wireless-G Broadband Router: NULL Pointer Dereference
CVE-2022-43972 is a high-severity NULL pointer dereference vulnerability in WRT54GL Wireless-G Broadband Router from Linksys, 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 WRT54GL Wireless-G Broadband Router versions: Firmware through 4.30.18.006. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.41% chance of exploitation within 30 days, higher than 73% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of WRT54GL Wireless-G Broadband Router you run against the affected versions below, and install the vendor's latest release.
- 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 |
|---|---|---|---|
| Linksys | WRT54GL Wireless-G Broadband Router | Firmware through 4.30.18.006 | Not stated |
| Linksys | Wrt54gl Firmware | 4.30.18.006 and earlier | Not stated |
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 NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.5 | Medium | CNA (trellix.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
A null pointer dereference vulnerability exists in Linksys WRT54GL Wireless-G Broadband Router with firmware <= 4.30.18.006. A null pointer dereference in the soap_action function within the upnp binary can be triggered by an unauthenticated attacker via a malicious POST request invoking the AddPortMapping action.
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: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Technical write-ups (may include proof of concept)
- youtu.be/73-1lhvJPNgExploit, Third Party Advisory
- youtu.be/RfWVYCUBNZ0Exploit, Third Party Advisory
- youtu.be/TeWAmZaKQ_wExploit, Third Party Advisory
Other vulnerabilities in WRT54GL Wireless-G Broadband Router
- 7.2 High severity
- 7.2 High severity
Recent NULL Pointer Dereference vulnerabilities
- 7.5 High severity
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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