hermes-webui: Improper Limitation of a Pathname to a Restricted Directory
CVE-2026-49957 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in hermes-webui from Nesquena, with a CVSS 3.1 base score of 7.7 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. The record lists version 0.51.296 as the first without the flaw, so updating hermes-webui to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.42% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update hermes-webui to 0.51.296 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Nesquena | hermes-webui | before 0.51.296 | 0.51.296 |
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
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 6.3 | Medium | CNA (vulncheck.com) |
| CVSS 3.1 | 7.7 | High | CNA (vulncheck.com) |
Official description
Hermes WebUI before version 0.51.296 contains a workspace boundary bypass vulnerability that allows authenticated attackers to circumvent blocked-root path checks by exploiting an early return in the SSH/remote terminal profile workspace resolution logic within _remote_terminal_workspace_candidate(). Attackers can configure a remote terminal working directory to a system directory such as /etc, causing the workspace resolution path to accept it as a trusted local workspace root before the _is_blocked_workspace_path() guard executes, enabling read access to local system files through workspace file-read helpers.
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.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Other vulnerabilities in hermes-webui
- 9.8 Critical severity
- 9.1 Critical severity
- 8.1 High severity
- 9.4 Critical severity
- 8.8 High severity
- 8.1 High severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 8.8 High severity
- 8.4 High severity
- 8.8 High severity
- 8.8 High severity
- 7.1 High severity
- 8.1 High severity
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