A950RG: Improper Restriction of Operations within the Bounds of a Memory Buffer
CVE-2026-121599 is a critical-severity improper restriction of operations within the bounds of a memory buffer vulnerability in A950RG from TOTOLINK, with a CVSS 3.1 base score of 9.9 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected A950RG versions: 4.1.2cu.5268_B20221104. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.47% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of A950RG you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. Scored by CNA (vuldb.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.6 | High | CNA (vuldb.com) |
| CVSS 3.1 | 9.9 | Critical | CNA (vuldb.com) |
| CVSS 2.0 | 9.0 | High | CNA (vuldb.com) |
Official description
A vulnerability was detected in TOTOLINK A950RG 4.1.2cu.5268_B20221104. Affected is the function setWiFiMultipleConfig/delWiFiMultipleConfig of the file /cgi-bin/cstecgi.cgi of the component Multi-SSID Configuration. The manipulation of the argument wepkey2/wepkey3 results in stack-based buffer overflow. It is possible to launch the attack remotely. The exploit is now public and may be used.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of Operations within the Bounds of a Memory Buffer
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.
How developers prevent this class of flaw
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in A950RG
- 9.9 Critical severity
- 9.9 Critical severity
- 9.9 Critical severity
- 10.0 Critical severity
- 9.9 Critical severity
- 9.1 Critical severity
Recent Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerabilities
- 7.5 High severity
- 9.6 Critical severity
- 9.6 Critical severity
- 8.4 High severity
- 7.5 High severity
- 8.4 High severity
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