CVE-2023-20240: Multiple vulnerabilities in Cisco Secure Client Software, formerly AnyConnect Secure Mobility Client, could al

Routine

MEDIUM 5.5DOWNGRADEDOWNGRADE

CVE-2023-20240 is a medium-severity flaw (CVSS 5.5) affecting anyconnect secure mobility client, secure client. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Multiple vulnerabilities in Cisco Secure Client Software, formerly AnyConnect Secure Mobility Client, could allow an authenticated, local attacker to cause a denial of service (DoS) condition on an affected system. These vulnerabilities are due to an out-of-bounds memory read from Cisco Secure Client Software. An attacker could exploit these vulnerabilities by logging in to an affected device at the same time that another user is accessing Cisco

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 90%)
CISA exploited list	No
Weakness	CWE-125
Published	2023-11-22
Last modified	2026-06-17

Publisher (CNA): Cisco Systems, Inc. · Vendor: cisco

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-11-22 17:15 UTCPublished CVE record published
2026-06-17 05:30 UTCUpdated Record last modified

cisco anyconnect secure mobility client DOWNGRADE

Affected: 4.9.00086 · 4.9.01095 · 4.9.02028 · 4.9.03047 · 4.9.03049 · 4.9.04043 · 4.9.04053 · 4.9.05042

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.9.00086

1. Check installed version

apt-cache policy anyconnect-secure-mobility-client || rpm -q anyconnect-secure-mobility-client || anyconnect-secure-mobility-client --version

2. No fixed release: DOWNGRADE to a release before 4.9.00086 (Debian / Ubuntu)

apt-cache madison anyconnect-secure-mobility-client sudo apt install anyconnect-secure-mobility-client=<VERSION_BEFORE_4.9.00086> sudo apt-mark hold anyconnect-secure-mobility-client

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list anyconnect-secure-mobility-client sudo dnf downgrade anyconnect-secure-mobility-client-<VERSION_BEFORE_4.9.00086> sudo dnf versionlock add anyconnect-secure-mobility-client

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

cisco secure client DOWNGRADE

Affected: 4.10.00093 · 4.10.01075 · 4.10.02086 · 4.10.03104 · 4.10.04065 · 4.10.04071 · 4.10.05085 · 4.10.05095

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.10.00093

1. Check installed version

apt-cache policy secure-client || rpm -q secure-client || secure-client --version

2. No fixed release: DOWNGRADE to a release before 4.10.00093 (Debian / Ubuntu)

apt-cache madison secure-client sudo apt install secure-client=<VERSION_BEFORE_4.10.00093> sudo apt-mark hold secure-client

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list secure-client sudo dnf downgrade secure-client-<VERSION_BEFORE_4.10.00093> sudo dnf versionlock add secure-client

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-20240?

anyconnect secure mobility client: downgrade or apply the listed mitigation; secure client: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-20240 being exploited?

CVE-2023-20240 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-20240 affect?

CVE-2023-20240 affects anyconnect secure mobility client, secure client. Severity is medium (CVSS 5.5). Multiple vulnerabilities in Cisco Secure Client Software, formerly AnyConnect Secure Mobility Client, could allow an authenticated, local attacker to cause a denial of service (DoS) condition on an affected system. These vulnerabilities are

How urgent is CVE-2023-20240?

Priority 22/100. No elevated risk signals yet.

Software pages

Cisco vulnerabilities

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References

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