X5000R: Improper Neutralization of Special Elements used in a Command
CVE-2026-91853 is a high-severity improper neutralization of special elements used in a command vulnerability in X5000R from TOTOLINK, with a CVSS 3.1 base score of 7.4 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 X5000R versions: 9.1.0cu.2089_B20211224. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.82% chance of exploitation within 30 days, higher than 79% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of X5000R 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
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L. Scored by CNA (vuldb.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 2.1 | Low | CNA (vuldb.com) |
| CVSS 3.1 | 7.4 | High | CNA (vuldb.com) |
| CVSS 2.0 | 6.5 | Medium | CNA (vuldb.com) |
Official description
A vulnerability has been found in TOTOLINK X5000R 9.1.0cu.2089_B20211224. The impacted element is the function exportOvpn of the file /cgi-bin/cstecgi.cgi?action=exportOvpn&type=user of the component Export Ovpn Handler. The manipulation of the argument filetype leads to os command injection. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements used in a Command
The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.
How developers prevent this class of flaw
- If at all possible, use library calls rather than external processes to recreate the desired functionality.
- If possible, ensure that all external commands called from the program are statically created.
- Run time: Run time policy enforcement may be used in an allowlist fashion to prevent use of any non-sanctioned commands.
More Improper Neutralization of Special Elements used in a Command vulnerabilities (CWE-77)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in X5000R
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
- 9.8 Critical severity
Recent Improper Neutralization of Special Elements used in a Command vulnerabilities
- 9.1 Critical severity
- 9.1 Critical severity
- 8.3 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 9.9 Critical severity
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