CVE-2021-1612

Authenticated file overwrite via symbolic-link placement

Published Sep 23, 2021 · Updated Nov 7, 2024

Symlink following in Cisco IOS XE SD-WAN Software allows local users to overwrite arbitrary files through the device CLI. The CLI follows a symbolic link placed at a specific filesystem location when writing, bypassing intended file access controls. Exploitation requires authenticated local CLI access and permits file-content replacement on the affected router, without reported disclosure or service interruption.

CVSS severity5.5
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Symlink following in Cisco IOS XE SD-WAN Software allows local users to overwrite arbitrary files through the device CLI. The CLI follows a symbolic link placed at a specific filesystem location when writing, bypassing intended file access controls. Exploitation requires authenticated local CLI access and permits file-content replacement on the affected router, without reported disclosure or service interruption.

The record

CVE
CVE-2021-1612
Published
Sep 23, 2021
Updated
Nov 7, 2024
Vendor
ClamAV
Product
Cisco IOS XE SD-WAN Software
Classifications
CWE-61, CAPEC-27, T1565.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 7, 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=n/a

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

ClamAV · Cisco IOS XE SD-WAN Softwareversion=n/a

Published CVSS scores

5.5CiscoCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-61UNIX Symbolic Link (Symlink) Following
CAPEC-27Leveraging Race Conditions via Symbolic Links
T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

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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