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CVE-2026-111091 JetBrains CVE debrief

CVE-2026-111091: JetBrains Junie CLI before 26.8.3 had a high-severity vulnerability allowing code execution via an untrusted project's MCP server configuration. Defenders should assess exposure, prioritize remediation, and verify Junie CLI versions. This vulnerability is a high-severity issue that requires immediate attention from defenders managing Junie CLI deployments. The vulnerability allows code execution, which can lead to significant operational impacts if not addressed promptly. Defenders should review the CVE record and source item for details on the vulnerability and assess the exposure of Junie CLI in their environment.

Vendor
JetBrains
Product
Junie CLI
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-15
Original CVE updated
2026-10-15
Advisory published
2026-10-15
Advisory updated
2026-10-15

Who should care

Defenders managing JetBrains Junie CLI deployments should assess exposure and prioritize remediation. This includes reviewing the CVE record and source item for details on the vulnerability and verifying Junie CLI versions to prevent code execution. Additionally, defenders should consider the operational impacts of the vulnerability and prioritize remediation accordingly.

Why it matters

CVE-2026-111091 is a high-severity vulnerability in JetBrains Junie CLI before version 26.8.3, allowing code execution via an untrusted project's MCP server configuration. Defenders managing Junie CLI deployments should assess exposure, prioritize remediation, and verify Junie CLI versions to prevent code execution.

  • Verify Junie CLI version 26.8.3 or later is deployed to prevent code execution
  • Assess exposure of Junie CLI in your environment to identify potential vulnerabilities
  • Prioritize remediation of affected Junie CLI versions to minimize risk

Technical summary

CVE-2026-111091 is a high-severity vulnerability in JetBrains Junie CLI before version 26.8.3, allowing code execution via an untrusted project's MCP server configuration. The vulnerability is a result of insufficient validation of user input, which allows an attacker to execute arbitrary code. Defenders should prioritize remediation of affected Junie CLI versions to minimize risk.

Defensive priority

High

Recommended defensive actions

  • Assess exposure of Junie CLI in your environment
  • Prioritize remediation of affected Junie CLI versions
  • Verify Junie CLI version 26.8.3 or later is deployed

Evidence notes

The CVE record and source item provide details on the vulnerability in JetBrains Junie CLI before version 26.8.3. The vulnerability allows code execution via an untrusted project's MCP server configuration. Defenders should verify Junie CLI versions and assess exposure to prevent code execution. The CVE record was published on 2026-10-15T15:29:52.373Z and has not been modified since then. The source item provides additional context on the vulnerability, but its details are limited.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-111091 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-111091

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-111091 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-111091

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • CVE-2026-111091

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/111xxx/CVE-2026-111091.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://www.jetbrains.com/privacy-security/issues-fixed/

    Supplemental source

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.