Acronis Backup's Incorrect Default Permissions Allow a Local Attacker to Access Backup Files and Configurations Not Intended for Their Account; CISA's September 19th KEV Deadline Has Passed

Last refreshed2026-09-27

Status: KEV | Advisory ID: CVE-2026-87886

Key Details

CVE	CVE-2026-87886
Vulnerability Name	Acronis Backup Incorrect Default Permissions Vulnerability
CVSS Score / Version	7.8 (High) / CVSS v3.0
Updated	2026-09-20
CVSS Vector	`CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`
CVSS Prose	attack vector is local; attack complexity is low; privileges required is low; user interaction is none; scope is unchanged; confidentiality impact is high; integrity impact is high; availability impact is high. Incorrect default file permissions in compiled code require a code update. On historical data platforms and backup systems typically allow ingest from multiple different platforms at high volume. These systems frequently also store confidential data and may have regulatory impact for data retention. These factors lead to higher exposure to embedded malicious code and significant impact from loss or compromise of the system. Expedited patching should be considered based on the system exposure and classification.
Affected products	Acronis Backup and Acronis Acronis Backup
Exploitation status	Listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, indicating confirmed active exploitation.
Classified as	CWE-276 (Incorrect Default Permissions)
KEV listing	Added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-09-16.
Exploitation prediction (EPSS)	0.23% probability of exploitation in the next 30 days (13% percentile) -- FIRST.org's EPSS model.
Federal remediation deadline	2026-09-19 (CISA KEV, Binding Operational Directive).

Affected Products, Subsystems & Sectors

Vendor	Product	Affected Versions	Patch Status
Acronis	Backup
Acronis	Acronis Backup

Vendor

Product

Affected Versions

Patch Status

Acronis

Backup

Acronis

Acronis Backup

Subsystems	Core Infrastructure, Historians/Industrial Data Platforms
Sectors	All Sectors, Chemical, Critical Manufacturing, Food and Agriculture

What to Know

Local privilege escalation due to insecure file permissions. The following products are affected: Acronis Backup plugin for cPanel & WHM (Linux) before build 1.9.3.1021, Acronis Backup extension for Plesk (Linux) before build 1.8.11.638, Acronis Backup plugin for DirectAdmin (Linux) before build 1.2.3.238.

What to Do

Monitor Acronis's web page for any future patch releases. See vendor advisory link below.

References

Source	Reference
NVD	https://nvd.nist.gov/vuln/detail/CVE-2026-87886
CVE	https://www.cve.org/CVERecord?id=CVE-2026-87886
Vendor advisory	https://security-advisory.acronis.com/advisories/SEC-10986

Source

Reference

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-87886

CVE

https://www.cve.org/CVERecord?id=CVE-2026-87886

Vendor advisory

https://security-advisory.acronis.com/advisories/SEC-10986

KEV Required Action

Field	Value
KEV Link	https://www.cisa.gov/known-exploited-vulnerabilities-catalog
Date Added to KEV	2026-09-16
Required Action Due Date	2026-09-19
Required Action	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.

Field

Value

KEV Link

https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Date Added to KEV

2026-09-16

Required Action Due Date

2026-09-19

Required Action

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.