CVE-2021-43566

Directory creation outside shares via symlink race

Published Jan 11, 2022 · Updated Aug 4, 2024

Share escape in Samba before 4.13.16 allows remote authenticated users to create directories outside an exported share. An SMB1 or NFS client renames an existing path and replaces it with a symlink after the share-path check, redirecting directory creation to any server path. The attacker needs write access to the share and directory-creation permission at the target, and must win a difficult race; SMB1 must be enabled or the share must also be exported through NFS.

CVSS severity2.5
Low
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Share escape in Samba before 4.13.16 allows remote authenticated users to create directories outside an exported share. An SMB1 or NFS client renames an existing path and replaces it with a symlink after the share-path check, redirecting directory creation to any server path. The attacker needs write access to the share and directory-creation permission at the target, and must win a difficult race; SMB1 must be enabled or the share must also be exported through NFS.

The record

CVE
CVE-2021-43566
Published
Jan 11, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-362
Attack vector
adjacent
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 11, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.5NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
2.6Amazon LinuxCVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
1.2NIST NVDAV:L/AC:H/Au:N/C:N/I:P/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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