CVE-2026-105818 HashiCorp CVE debrief

Who should care

Defenders managing Vault PKI configurations, especially those using ACME, should assess exposure and verify configurations to prevent potential impersonation attacks. This includes reviewing the affected Vault versions and updating to fixed versions: Vault Community Edition 2.1.2, Vault Enterprise 2.1.2, 1.21.12, 1.20.17, and 1.19.23. Additionally, defenders should review compensating controls and monitor for potential security incidents.

Why it matters

Defenders should prioritize verifying Vault PKI configurations, especially those using ACME, and assess exposure in their environments to prevent potential impersonation attacks.

• Potential impersonation toward systems trusting certificates from the affected Vault PKI mount
• Need to verify Vault PKI configurations and assess exposure
• Priority to update to fixed versions to prevent certificate issuance with unverified identities

Technical summary

The vulnerability in Vault's PKI secrets engine ACME server allows issuance of certificates with unverified identity claims. This issue arises because the ACME server does not restrict certificate identities that ACME challenges do not validate. The vulnerability is fixed in Vault Community Edition 2.1.2 and Vault Enterprise 2.1.2, 1.21.12, 1.20.17, and 1.19.23. Defenders should prioritize verifying Vault PKI configurations, especially those using ACME, and assess exposure in their environments to prevent potential impersonation attacks.

Defensive priority

Defenders should prioritize verifying Vault PKI configurations, especially those using ACME, and assess exposure in their environments.

Recommended defensive actions

• Verify Vault PKI configurations, especially those using ACME
• Assess exposure in environments using affected Vault versions
• Update to fixed versions: Vault Community Edition 2.1.2, Vault Enterprise 2.1.2, 1.21.12, 1.20.17, and 1.19.23
• 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 source item provide details on the vulnerability and affected versions. However, additional information on exploitation or specific impacts is limited. Defenders should verify Vault PKI configurations, especially those using ACME, and assess exposure in their environments. The vulnerability allows issuance of certificates with unverified identity claims, potentially enabling impersonation attacks. There is no evidence of exploitation in the wild, but defenders should prioritize verification and updates.

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.