CVE-2026-109156 SeldonIO CVE debrief

Who should care

Defenders responsible for SeldonIO MLServer deployments should assess exposure and prioritize verification of affected versions. This vulnerability may pose a significant risk to exposed systems due to its remote attack vector and medium CVSS score.

Why it matters

CVE-2026-109156 is a path traversal vulnerability in SeldonIO MLServer that allows remote attackers to manipulate environment variables. Defenders should verify affected versions, monitor for suspicious activity, and adjust access controls to mitigate this medium-severity vulnerability.

• Verify and update SeldonIO MLServer versions to prevent exploitation
• Monitor environment variables for suspicious activity
• Adjust access controls for the environment_tarball handler

Technical summary

The _extract_env function in mlserver/env.py is vulnerable to path traversal attacks, allowing remote manipulation of environment variables. This issue affects SeldonIO MLServer versions up to 1.6.1. The vulnerability has a medium CVSS score of 5.3 and can be exploited remotely. Defenders should prioritize verifying the affected versions of SeldonIO MLServer in their environment and consider updating to a patched version if available. The vendor, SeldonIO, was contacted but did not respond to the disclosure. Additional sources, such as VulDB, offer technical descriptions and indicators of compromise.

Defensive priority

Defenders should prioritize verifying the affected versions of SeldonIO MLServer in their environment and consider updating to a patched version if available. Given the remote attack vector and medium CVSS score of 5.3, this vulnerability may pose a significant risk to exposed systems.

Recommended defensive actions

• Verify SeldonIO MLServer versions up to 1.6.1 for exposure
• Consider updating to a patched version if available
• Monitor environment variables for suspicious activity
• Review and adjust access controls for the environment_tarball handler
• Perform a thorough review of system logs to identify potential malicious activity
• Implement additional monitoring to detect anomalies in environment variables
• Conduct a thorough asset inventory to identify all instances of SeldonIO MLServer

Evidence notes

The CVE Program record and NVD vulnerability detail provide official information about the vulnerability. Additional sources, such as VulDB, offer technical descriptions and indicators of compromise. However, the vendor did not respond to the disclosure.

Sources and 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.