VPN Agent crash via out-of-bounds packet read
Published Nov 22, 2023 · Updated Jun 5, 2025
An out-of-bounds read in Cisco Secure Client 5.0.04032 and earlier allows local users to crash the VPN Agent with crafted packets. The VPN Agent reads beyond a memory buffer while processing packets sent to a local host port, terminating the service. Exploitation requires valid local credentials on a multi-user system and concurrent client access by another user; a crash interrupts VPN service for every user.
Summary
What happened
An out-of-bounds read in Cisco Secure Client 5.0.04032 and earlier allows local users to crash the VPN Agent with crafted packets. The VPN Agent reads beyond a memory buffer while processing packets sent to a local host port, terminating the service. Exploitation requires valid local credentials on a multi-user system and concurrent client access by another user; a crash interrupts VPN service for every user.
The record
- CVE
- CVE-2023-20241
- Published
- Nov 22, 2023
- Updated
- Jun 5, 2025
- Vendor
- ClamAV
- Product
- Cisco Secure Client
- Classifications
- CWE-125, CAPEC-540, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Nov 22, 2023CVE publishedPublication date reported by the CVE source.
- Jun 5, 2025Record 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.
- Affected versionversion=4.10.00093
- Affected versionversion=4.10.01075
- Affected versionversion=4.10.02086
- Affected versionversion=4.10.03104
- Affected versionversion=4.10.04065
- Affected versionversion=4.10.04071
- Affected versionversion=4.10.05085
- Affected versionversion=4.10.05095
- Affected versionversion=4.10.05111
- Affected versionversion=4.10.06079
- Affected versionversion=4.10.06090
- Affected versionversion=4.10.07061
- Affected versionversion=4.10.07062
- Affected versionversion=4.10.07073
- Affected versionversion=4.9.00086
- Affected versionversion=4.9.01095
- Affected versionversion=4.9.02028
- Affected versionversion=4.9.03047
- Affected versionversion=4.9.03049
- Affected versionversion=4.9.04043
- Affected versionversion=4.9.04053
- Affected versionversion=4.9.05042
- Affected versionversion=4.9.06037
- Affected versionversion=5.0.00238
- Affected versionversion=5.0.00529
- Affected versionversion=5.0.00556
- Affected versionversion=5.0.01242
- Affected versionversion=5.0.02075
- Affected versionversion=5.0.03072
- Affected versionversion=5.0.03076
- Affected versionversion=5.0.04032
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
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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