CVE-2026-124028
mistral.rs before 0.9.5 Tool Call Injection via mistralrs-core Output Parsers
CVE-2026-124028 is a low vulnerability (CVSS 2.3) in Ericlbuehler Mistral.rs, published November 6, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.19%, the 8th percentile. No source names a fixed version.
- Severity
- 2.3 LowCVSS 4.0, CVE List
- Exploit chance
- 0.19%EPSS, 8th percentile
- Exploitation
- None knownNot on CISA’s or ENISA’s lists
- Fixed in
- No fix listedNo source names one
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
Affected products
What each source reports
CVE List Score used
mistral.rs before 0.9.5 Tool Call Injection via mistralrs-core Output Parsers
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.
- Record
CVE-2026-124028- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 4.2 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N - Weakness
- CWE-140
- Updated
- 2026-11-09
EUVDEUVD-2026-118436
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.
- Record
EUVD-2026-118436- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-07
GitHub AdvisoriesGHSA-g3jq-5q72-jc6f
mistral.rs before 0.9.5 contains a delimiter injection vulnerability in mistralrs-core that...
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.
- Record
GHSA-g3jq-5q72-jc6f- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 4.2 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N - Weakness
- CWE-140
- Updated
- 2026-11-06
NVD
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.
- Record
CVE-2026-124028- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 4.2 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N - Weakness
- CWE-140
- Updated
- 2026-11-09
OSV
mistral.rs before 0.9.5 Tool Call Injection via mistralrs-core Output Parsers
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.
- Record
CVE-2026-124028- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-140
- Updated
- 2026-11-08
History
| Recorded | Changed | Sources |
|---|---|---|
| references | CVE List, OSV | |
| aliases, references | OSV | |
| published | EUVD | |
| published | EUVD, NVD | |
| aliases, references | GitHub Advisories | |
| cwes, references, severity, title | CVE List | |
| first indexed | EUVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
References
github.com/EricLBuehler/mistral.rs/commit/b43d3443e946752c0f662c2df42a2974410c9532
vulncheck.com/advisories/mistral-rs-before-0.9.5-tool-call-injection-via-mistralrs-core-output-parsers
nvd.nist.gov/vuln/detail/CVE-2026-124028