ChatCLI: Origin Validation Error
CVE-2026-123271 is a high-severity origin validation error vulnerability in ChatCLI from Diillson, with a CVSS 3.1 base score of 8.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version v1.215.2 as the first without the flaw, so updating ChatCLI to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.15% 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 ChatCLI to v1.215.2 or a later version.
- Read the advisory on github.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.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Diillson | ChatCLI | v1.159.0 up to, but not including, v1.215.2 | v1.215.2 |
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
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 5.1 | Medium | CNA (vulncheck.com) |
| CVSS 3.1 | 8.0 | High | CNA (vulncheck.com) |
Official description
ChatCLI before v1.215.2 contains an improper validation vulnerability in the MCP OAuth login flow that uses server-supplied Protected Resource Metadata as the resource indicator without checking it matches the configured server URL. A malicious MCP server can declare another resource on the same authorization server, obtain the user's bearer token for it, and replay that token against the other resource.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Origin Validation Error
The product does not properly verify that the source of data or communication is valid.
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
Recent Origin Validation Error vulnerabilities
- 8.0 High severity
- 9.1 Critical severity
- 7.1 High severity
- 9.1 Critical severity
- 9.3 Critical severity
- 8.8 High severity
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