ex200_firmware: Failure to Sanitize Special Elements into a Different Plane
CVE-2024-31809 is a high-severity failure to sanitize special elements into a different plane vulnerability in ex200_firmware from TOTOLINK, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected ex200_firmware versions: 4.0.3c.7646_b20201211. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.98% chance of exploitation within 30 days, higher than 63% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of ex200_firmware you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| TOTOLINK | ex200_firmware | 4.0.3c.7646_b20201211 | 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
- AdjacentThe attacker must be on the same local network segment.
- 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
- 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:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
TOTOLINK EX200 V4.0.3c.7646_B20201211 was discovered to contain a remote code execution (RCE) vulnerability via the FileName parameter in the setUpgradeFW function.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Failure to Sanitize Special Elements into a Different Plane
The product does not adequately filter user-controlled input for special elements with control implications.
How developers prevent this class of flaw
- Programming languages and supporting technologies might be chosen which are not subject to these issues.
- Utilize an appropriate mix of allowlist and denylist parsing to filter special element syntax from all input.
More Failure to Sanitize Special Elements into a Different Plane vulnerabilities (CWE-75)
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
Technical write-ups (may include proof of concept)
- github.com/4hsien/CVE-vulns/blob/main/TOTOLINK/EX200/CI_4_setUpgradeFW/CI.mdExploit, Third Party Advisory
Other vulnerabilities in ex200_firmware
- 8.8 High severity
- 8.8 High severity
- 8.0 High severity
- 8.8 High severity
- 9.8 Critical severity
Recent Failure to Sanitize Special Elements into a Different Plane vulnerabilities
- 7.2 High severity
- 8.1 High severity
- 9.0 Critical severity
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