Mailinspector: External Control of File Name or Path
CVE-2026-29962 is a high-severity external control of file name or path vulnerability in Mailinspector from Hsclabs, 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 Mailinspector versions: 5.3.3-7. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.53% chance of exploitation within 30 days, higher than 75% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Mailinspector 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 |
|---|---|---|---|
| Hsclabs | Mailinspector | 5.3.3-7 | Not stated |
Version data comes from NVD's product matching. 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
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by CISA (ADP).
Official description
HSC MailInspector v5.3.3-7 contains a Local File Inclusion (LFI) vulnerability caused by improper control of user-supplied file paths. The endpoint /vendor/phpunit/phpunit.php processes user-controlled parameters that directly affect file access operations without adequate validation, sanitization, or path restriction. This allows a remote attacker to exploit Path Traversal techniques to read arbitrary files from the underlying operating system and application directories, leading to sensitive information disclosure.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: External Control of File Name or Path
The product allows user input to control or influence paths or file names that are used in filesystem operations.
How developers prevent this class of flaw
- When the set of filenames is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames, and reject all other inputs. For example, ID 1 could map to inbox.txt and ID 2 could map to profile.txt. Features such as the ESAPI AccessReferenceMap provide this capability.
- Run your code in a jail or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict all access to files within a particular directory. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
- 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.
More External Control of File Name or Path vulnerabilities (CWE-73)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- github.com/sql3t0/cve-disclosuresThird Party Advisory
- github.com/sql3t0/cve-disclosures/blob/main/01_-_CVE-2026-29962_LFI%2BPath_Traversal.mdThird Party Advisory
Other references
Other vulnerabilities in Mailinspector
- 7.5 High severity
Recent External Control of File Name or Path vulnerabilities
- 8.2 High severity
- 8.1 High severity
- 8.8 High severity
- 7.5 High severity
- 7.8 High severity
- 9.6 Critical severity
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