CVE-2026-87886: Acronis Backup Incorrect Default Permissions Vulnerability

CISA Known Exploited Vulnerability (KEV)

Description

Acronis Backup plugin for cPanel & WHM and extension for Plesk contains an incorrect default permissions vulnerability that could allow for privilege escalation.

Required action (CISA)

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Notes

https://security-advisory.acronis.com/advisories/SEC-10986 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-87886

Weakness behind it

CISA records this vulnerability as an instance of CWE-276. From there the chain continues into CAPEC attack patterns and ATT&CK techniques, all inside this corpus.

References

• NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-87886
• KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog