CVE-2026-100871 Sylius CVE debrief

Who should care

Defenders responsible for Sylius deployments, security teams, and vulnerability management teams should assess exposure and prioritize patching. Operators and administrators of affected systems must verify inventory, apply patches, and monitor for suspicious activity to mitigate potential operational impacts.

Why it matters

CVE-2026-100871 is a high-severity vulnerability in Sylius that allows attackers to gain full administrative access. Defenders should prioritize verifying inventory, applying patches, and monitoring for suspicious activity.

• Potential for attackers to gain full administrative access
• Need for verification of affected versions and inventory
• Priority for patching and remediation
• Potential for monitoring and detection of suspicious activity

Technical summary

Sylius versions before 1.12.25, 1.13.17, 1.14.20, 2.1.16, and 2.2.9 fail to include firewall identification in JWT tokens issued by separate Admin and Shop API endpoints. This oversight allows attackers to register a shop customer account using an administrator's email address and obtain a token that the Admin API resolves to that administrator, granting full administrative access. The vulnerability is a result of JWT audience confusion, highlighting the need for defenders to prioritize verifying inventory and applying patches.

Defensive priority

Defenders should prioritize verifying inventory and applying patches for Sylius versions before 1.12.25, 1.13.17, 1.14.20, 2.1.16, and 2.2.9.

Recommended defensive actions

• Verify Sylius inventory for versions before 1.12.25, 1.13.17, 1.14.20, 2.1.16, and 2.2.9
• Apply patches for affected Sylius versions
• Monitor for suspicious Admin API activity
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability. Additional verification is required to confirm affected versions and remediation. Defenders should verify inventory, apply patches, and monitor for suspicious activity. The vulnerability's high severity and potential for full administrative access necessitate prompt action.

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.