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CVE-2026-34371 danny-avila CVE debrief

CVE-2026-34371 is an arbitrary file write vulnerability in LibreChat, a ChatGPT clone, prior to version 0.8.4. The execute_code sandbox feature trusts user-inputted filenames, allowing malicious users to write files to arbitrary locations on the server using traversal sequences. This vulnerability can be exploited by providing a malicious filename containing traversal sequences, which is then concatenated into the server-side destination path and written with fs.writeFileSync() without proper sanitization. As a result, an attacker can achieve an arbitrary file write primitive as the LibreChat server user. Users of LibreChat versions prior to 0.8.4 should be aware of this vulnerability and take immediate action to upgrade. The vulnerability has a CVSS score of 6.3 and a severity of MEDIUM. Evidence is limited to public sources and may not reflect the full scope or impact of the vulnerability.

Vendor
danny-avila
Product
LibreChat
CVSS
MEDIUM 6.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-07
Original CVE updated
2026-07-24
Advisory published
2026-04-07
Advisory updated
2026-07-24

Who should care

Users of LibreChat versions prior to 0.8.4 should be aware of this vulnerability and take immediate action to upgrade. Security teams monitoring for potential file write attacks should also prioritize this CVE.

Technical summary

The vulnerability exists in the execute_code sandbox feature of LibreChat. When a user triggers the execute_code feature, the application trusts the name field returned by the sandbox and uses it to persist code-generated artifacts. On deployments using the default local file strategy, an attacker can provide a malicious filename containing traversal sequences (e.g., ../../../../../app/client/dist/poc.txt). This filename is concatenated into the server-side destination path and written with fs.writeFileSync() without proper sanitization, allowing an arbitrary file write primitive as the LibreChat server user.

Defensive priority

High

Recommended defensive actions

  • Upgrade LibreChat to version 0.8.4 or later
  • Review and sanitize user-inputted filenames in the execute_code sandbox
  • Implement additional monitoring for potential file write attacks
  • Restrict access to the execute_code feature to trusted users
  • Perform a thorough review of system logs to detect potential exploitation attempts
  • Conduct a vulnerability scan to identify potentially affected systems
  • Establish a remediation timeline based on risk assessment and resource availability

Evidence notes

The CVE record was published on 2026-04-07T22:16:22.227Z and last modified on 2026-07-24T22:10:00.140Z. The NVD entry is currently Analyzed. The vulnerability has a CVSS score of 6.3 and a severity of MEDIUM. Evidence is limited to public sources and may not reflect the full scope or impact of the vulnerability. Defenders should verify affected deployments and review official advisories for specific guidance.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-34371 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-34371

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

  • CVE-2026-34371 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-34371

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

Supplemental references

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.