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PatchSiren cyber security CVE debrief

CVE-2026-22218 Chainlit CVE debrief

CVE-2026-22218 is a high-severity vulnerability in Chainlit versions prior to 2.9.4. An authenticated client can exploit the /project/element update flow by sending a custom Element with a user-controlled path value, leading to arbitrary file disclosure. This vulnerability allows an attacker to read any file that is readable by the Chainlit service.

Vendor
Chainlit
Product
Unknown
CVSS
HIGH 7.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-01-20
Original CVE updated
2026-07-14
Advisory published
2026-01-20
Advisory updated
2026-07-14

Who should care

Users of Chainlit versions prior to 2.9.4 should apply the patch to prevent unauthorized file disclosure. This includes administrators and security teams responsible for maintaining Chainlit instances, as well as developers who use Chainlit in their applications.

Technical summary

The vulnerability exists in the /project/element update flow of Chainlit. An authenticated client can send a custom Element with a user-controlled path value, causing the server to copy the referenced file into the attacker’s session. The resulting element identifier (chainlitKey) can then be used to retrieve the file contents via /project/file/<chainlitKey>, allowing disclosure of any file readable by the Chainlit service. This issue is particularly concerning because it allows for the potential disclosure of sensitive files.

Defensive priority

High

Recommended defensive actions

  • Apply the patch to upgrade Chainlit to version 2.9.4 or later.
  • Restrict access to the /project/element update flow and /project/file/ endpoints.
  • Monitor for suspicious activity on the Chainlit service.
  • Perform regular inventory checks to ensure all Chainlit instances are up-to-date.
  • Implement compensating controls, such as file access controls and monitoring.
  • Review and update security configurations to prevent similar vulnerabilities.
  • Conduct a thorough review of the Chainlit service to identify potential security risks.

Evidence notes

The CVE record was published on 2026-01-20T00:15:48.910Z and has not been modified since then. The NVD entry is currently Analyzed. There are no additional details available beyond what is provided in the CVE record and NVD entry.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-22218 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-22218

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

  • CVE-2026-22218 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-22218

    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.