CVE-2021-23002Public exploit

VPN session hijacking via exposed command arguments

Published Mar 31, 2021 · Updated Aug 3, 2024

Information disclosure in F5 BIG-IP APM and Edge Client allows local users to obtain a VPN session ID from a Windows process command line. When a browser launches f5vpn.exe, the VPN workflow passes the session identifier as a command-line argument visible through process inspection. Access requires visibility into the process arguments during an authenticated user's VPN launch; the exposed identifier enables session hijacking with that user's access.

CVSS severity4.5
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in F5 BIG-IP APM and Edge Client allows local users to obtain a VPN session ID from a Windows process command line. When a browser launches f5vpn.exe, the VPN workflow passes the session identifier as a command-line argument visible through process inspection. Access requires visibility into the process arguments during an authenticated user's VPN launch; the exposed identifier enables session hijacking with that user's access.

The record

CVE
CVE-2021-23002
Published
Mar 31, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1539
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Mar 31, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 vectorlocal
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.7NIST NVDAV:A/AC:L/Au:S/C:P/I:N/A:N
4.5NIST NVDCVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:N/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 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

T1539Steal Web Session Cookie

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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