Mattermost: Improper Limitation of a Pathname to a Restricted Directory
CVE-2023-6458 is a critical-severity improper limitation of a pathname to a restricted directory vulnerability in Mattermost, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Mattermost versions: 9.1.1 and earlier; 9.0.2 and earlier; 8.1.4 and earlier, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.64% chance of exploitation within 30 days, higher than 51% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Mattermost Server to 7.8.14 or 8.1.5 or 9.0.3 or 9.1.2, whichever matches your release line, or a later version.
- Read the advisory on mattermost.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 |
|---|---|---|---|
| Mattermost | Mattermost | 9.1.1 and earlier; 9.0.2 and earlier; 8.1.4 and earlier; 7.8.13 and earlier | Not stated |
| Mattermost | Mattermost Server | before 7.8.14; 8.0.0 up to, but not including, 8.1.5; 9.0.0 up to, but not including, 9.0.3; 9.1.0 up to, but not including, 9.1.2 | 7.8.14, 8.1.5, 9.0.3, 9.1.2 |
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
- 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:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.1 | High | CNA (mattermost.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
Mattermost webapp fails to validate route parameters in/<TEAM_NAME>/channels/<CHANNEL_NAME> allowing an attacker to perform a client-side path traversal.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Mattermost
- 8.0 High severity
- 7.1 High severity
- 9.3 Critical severity
- 7.1 High severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 8.8 High severity
- 9.1 Critical severity
- 8.8 High severity
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