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Collection Degraded30 / 46 Sources HealthyPublic Intel Only
Vulnerabilities/CVE-2026-87886Public Intelligence Dossier
Source: acronis · Limited verification•Last verified: •Collection Degraded
CVE-2026-87886ListedHIGH (raw)CVSS 7.8CWE-276

Local privilege escalation due to insecure file permissions

Published: 18 Sept 2026•Last updated: 19 Sept 2026, 12:59 AM IST•Source identifier: security@acronis.com
Dossier completeness: source-provided sections 3 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Listed
Added16 Sept 2026
Due19 Sept 2026
RansomwareUnknown
CVSS score
7.8HIGH (raw)
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Metric sourcesecurity@acronis.com
EPSS probability
—
Percentile—
Weakness type
CWE-276
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

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.

SOC priority

Immediate Attention

Actively exploited

Yes

Publicly disclosed

Unknown

Risk basis: CISA KEV exploitation signal; SOC ecosystem technology relevance; HIGH severity; Known exploitation signal from CISA KEV or ransomware metadata

Affected Products & Remediation

1 source-backed product
Affected products and versions (source)
  • acronis acronis backup · < 1.2.3; < 1.8.11; < 1.9.3; 1.9.3 · NVD CPE · Source
NVD applicability prerequisites: cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*. These are conditions, not proof that an environment is exposed or unaffected.
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

  • CISA KEV: 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.

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Listed
Exploited (source statement)
Yes
Publicly disclosed (source)
Unknown

CISA 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.

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched local-privilege-escalation (CVSS AV:L, CVSS PR:L)

Exposure

  1. Identify hosts reporting this CVE, prioritising shared or multi-user systems.Telemetry: DeviceTvmSoftwareVulnerabilities · A local, low-privilege vector matters most where untrusted users can run code. · Rule local-privilege-escalation

Exploitation evidence

  1. Look for low-privileged processes spawning SYSTEM or root-level child processes on affected hosts.Telemetry: DeviceProcessEvents · Hunting hypothesis from the CVSS vector; privilege transitions are a focused starting point, not evidence of attack. · Rule local-privilege-escalation

Response

  1. Confirm the source-stated update on affected hosts.Telemetry: DeviceTvmSoftwareVulnerabilities · Host inventory can verify remediation. · Rule local-privilege-escalation

CISA KEV Record

Catalog entry
16 Sept 2026
Required action due
19 Sept 2026
Known ransomware use
Unknown

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.

Change History & Source Data

— No recorded material change

CNA / source
security@acronis.com
Record status · verification
NEW · CISA KEV confirmed
CPE
cpe:2.3:a:acronis:acronis_backup:*:*:*:*:*:directadmin:*:*, cpe:2.3:a:acronis:acronis_backup:*:*:*:*:*:plesk:*:*, cpe:2.3:a:acronis:acronis_backup:*:*:*:*:*:cpanel:*:*, cpe:2.3:a:acronis:acronis_backup:1.9.3:-:*:*:*:cpanel:*:*, cpe:2.3:a:acronis:acronis_backup:1.9.3:hotfix1:*:*:*:cpanel:*:*, cpe:2.3:a:acronis:acronis_backup:1.9.3:hotfix2:*:*:*:cpanel:*:*, cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*

Evidence & Provenance

4 public sources
CISA KEV CatalogAdded 2026-09-16security-advisory.acronis.comSource recordnvd.nist.govSource recordcisa.govSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2026-87886
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-87886
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-87886"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

Correlated briefings

— No published briefing references this CVE

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.