CVE-2026-124028 Details
Description
mistral.rs before 0.9.5 contains a delimiter injection vulnerability in mistralrs-core that allows attackers to inject tool calls by placing delimiter strings in text the model quotes. Attackers controlling documents, web pages or tool outputs can embed tags like </tool_call> to make qwen-xml, gemma4 or reasoning parsers return extra calls to declared tools with attacker-chosen arguments.
A delimiter injection vulnerability has been identified in mistral.rs versions prior to 0.9.5, specifically within the mistralrs-core component. This vulnerability allows attackers to inject tool calls by embedding delimiter strings in text that the model quotes. When the model processes this text, it can inadvertently close an existing tool call or argument and open a new one, leading to the injection of unauthorized tool calls with attacker-chosen arguments. The issue arises when documents, web pages, or tool outputs controlled by the attacker are processed by the model.
Users can upgrade to mistral.rs version 0.9.5 or later, where this vulnerability has been patched.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Nov 6, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-140 | Improper Neutralization of Delimiters | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| EricLBuehler mistral.rs | < 0.9.5 (semver) |
CPE
Remediation
| |
| EricLBuehler mistralrs-core | < 0.9.5 (semver) |
CPE
Remediation
| |
Change History
1 change record found show changes
| Date | Action | Recorded By |
|---|---|---|
| Nov 6, 2026 | New CVE Received | [email protected] |