CVE-2021-26563Public exploit

Sandbox escape via permitted kernel-module loading

Published Feb 26, 2021 · Updated Sep 16, 2024

Incorrect authorization in synoagentregisterd in Synology DiskStation Manager before 6.2.4-25553 allows local users to execute arbitrary code. The linked Talos report attributes the flaw to a synosearchagent AppArmor profile that permits its root-confined process to load crafted kernel modules and unload AppArmor. Exploitation requires prior root-level code execution inside that confined context; a successful escape grants unrestricted root access to DSM.

CVSS severity8.2
High
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in synoagentregisterd in Synology DiskStation Manager before 6.2.4-25553 allows local users to execute arbitrary code. The linked Talos report attributes the flaw to a synosearchagent AppArmor profile that permits its root-confined process to load crafted kernel modules and unload AppArmor. Exploitation requires prior root-level code execution inside that confined context; a successful escape grants unrestricted root access to DSM.

The record

CVE
CVE-2021-26563
Published
Feb 26, 2021
Updated
Sep 16, 2024
Vendor
Synology
Product
DiskStation Manager
Classifications
CWE-863, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Feb 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <6.2.4-25553

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Synology · DiskStation Managerversion=unspecified <6.2.4-25553

Published CVSS scores

6.7NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
4.6NVDAV:L/AC:L/Au:N/C:P/I:P/A:P
8.2SynologyCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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