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CVE-2026-87886 (GCVE-0-2026-87886)

Vulnerability from cvelistv5 – Published: 2026-09-17 22:57 – Updated: 2026-09-18 14:33
VLAI CISA Previdian
Summary
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.
Severity
7.8 (High)
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: active Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-18 12:27 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
Acronis Acronis Backup plugin for cPanel & WHM Affected: unspecified , < 1.9.3.1021 (semver)
guessed Create a notification for this product.
Acronis Acronis Backup extension for Plesk Affected: unspecified , < 1.8.11.638 (semver)
guessed Create a notification for this product.
Acronis Acronis Backup plugin for DirectAdmin Affected: unspecified , < 1.2.3.238 (semver)
guessed Create a notification for this product.
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 320a50a7-980d-4162-b090-c53849c01837

Vulnerability ID: CVE-2026-87886

Status: Confirmed

Status Updated: 2026-09-16 00:00 UTC

Exploited: Yes

Timestamps
First Seen: 2026-09-16
Asserted: 2026-09-16
Scope
Notes: Acronis Backup Incorrect Default Permissions Vulnerability | Affected: Acronis / Backup | 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: 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. | Due date: 2026-09-19 | Known ransomware campaign use (KEV): Unknown | Notes (KEV): 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
Evidence

Type: Vendor Report

Signal: Successful Exploitation

Confidence: 80%

Source: cisa-kev

Details
Cwes CWE-276
Feed CISA Known Exploited Vulnerabilities Catalog
Product Backup
Due Date 2026-09-19
Date Added 2026-09-16
Vendorproject Acronis
Vulnerabilityname Acronis Backup Incorrect Default Permissions Vulnerability
Knownransomwarecampaignuse Unknown
References
Created: 2026-09-16 20:00 UTC | Updated: 2026-09-16 20:00 UTC
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 5c238c9c-ce9f-448b-b2cf-c1ad073c5b59

Vulnerability ID: CVE-2026-87886

Status: Confirmed

Status Updated: 2026-09-15 21:57 UTC

Exploited: Yes

Timestamps
First Seen: 2026-09-15
Asserted: 2026-09-15
Scope
Notes: Acronis Backup plugin Local privilege escalation due to insecure file permissions | Affected: Acronis / Acronis Backup | CVSS: 7.8 (HIGH) | Used in malware: unknown | Listed 21 hours ahead of CISA KEV | Not yet in CISA KEV: False
Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: previdian

Details
Feed Previdian (previdian.com)
Title Acronis Backup plugin Local privilege escalation due to insecure file permissions
Cve Id CVE-2026-87886
Vendor Acronis
Ghsa Id None
Product Acronis Backup
Added Date 2026-09-15T21:57:00.000Z
Cvss Score 7.8
Epss Score None
Previous Ids
Cvss Severity HIGH
Virtual Patch False
Cvss Estimated False
Epss Percentile None
Used In Malware unknown
Vulnerability Id CVE-2026-87886
Ahead Of Cisa Kev 
{
  "count": 21,
  "unit": "hour"
}
Not Yet In Cisa Kev False
References
Created: 2026-09-16 22:00 UTC | Updated: 2026-09-16 22:00 UTC
Show details on NVD website
To clipboard 

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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.