🛡️ CVE-2024-3661 — anyconnect-vpn-client
Description
DHCP can add routes to a client’s routing table via the classless static route option (121). VPN-based security solutions that rely on routes to redirect traffic can be forced to leak traffic over the physical interface. An attacker on the same local network can read, disrupt, or possibly modify network traffic that was expected to be protected by the VPN.
How this vulnerability can be exploited
This issue can be reached from an adjacent network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity low, availability low.
CVSS metrics in full
The score comes from this vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
- Attack vector: Adjacent network — the attacker has to sit on the same local or logical network.
- Attack complexity: Low — the attack works reliably, with no preparation.
- Privileges required: None — an unauthenticated stranger can try it.
- User interaction: None — nobody has to be tricked into anything.
- Scope: Unchanged — the damage stays inside the vulnerable component.
- Confidentiality impact: High — total loss, or loss the attacker controls.
- Integrity impact: Low — limited, and the attacker does not choose what is affected.
- Availability impact: Low — limited, and the attacker does not choose what is affected.
Weakness class
CVE-2024-3661 is classified as CWE-306: Missing Authentication for Critical Function. A sensitive function can be reached without authenticating at all.
Affected software
CVE-2024-3661 is recorded against 9 packages.
- anyconnect-vpn-client
- big-ip-access-policy-manager (from 17.1.0 up to 17.1.2)
- client-connector
- forticlient
- globalprotect
- ipsec-mobile-vpn-client
- mobile-vpn-with-ssl
- secure-access-client (fixed in 24.8.5)
- secure-client
Timeline and source
Published on 6 May 2024 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. Record sourced from NVD.
References
arstechnica.com
bst.cisco.com
datatracker.ietf.org
datatracker.ietf.org
fortiguard.fortinet.com
issuetracker.google.com
krebsonsecurity.com
lowendtalk.com
mullvad.net
my.f5.com
news.ycombinator.com
news.ycombinator.com
security.paloaltonetworks.com
support.citrix.com
tunnelvisionbug.com
www.agwa.name
www.leviathansecurity.com
www.theregister.com
www.watchguard.com
www.zscaler.com
arstechnica.com
bst.cisco.com
datatracker.ietf.org
datatracker.ietf.org
fortiguard.fortinet.com
issuetracker.google.com
krebsonsecurity.com
lowendtalk.com
mullvad.net
my.f5.com
news.ycombinator.com
news.ycombinator.com
security.paloaltonetworks.com
support.citrix.com
tunnelvisionbug.com
www.agwa.name
www.leviathansecurity.com
www.theregister.com
www.watchguard.com
www.zscaler.com
Same weakness in other software
These advisories are the same class of weakness (CWE-306: Missing Authentication for Critical Function) in other software:
- CVE-2026-18941 (7.7 High, published 10 Aug 2026)
- CVE-2025-15681 (published 10 Aug 2026)
- CVE-2026-15581 (8.0 High, published 10 Aug 2026)
- CVE-2025-71409 (7.1 High, published 7 Aug 2026)
- CVE-2026-24079 (8.1 High, published 4 Aug 2026)
- CVE-2026-17348 (6.5 Medium, published 31 Jul 2026)
- CVE-2026-15978 (7.5 High, published 30 Jul 2026)
- CVE-2026-12722 (8.2 High, published 30 Jul 2026)
CVE-2024-3661 on other distributions
Each distribution ships its own build and its own fixed version. Pick the one you run:
Details
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| anyconnect-vpn-client | — | — |
| big-ip-access-policy-manager | 17.1.0 | 17.1.2 |
| client-connector | — | — |
| forticlient | — | — |
| globalprotect | — | — |
| ipsec-mobile-vpn-client | — | — |
| mobile-vpn-with-ssl | — | — |
| secure-access-client | — | 24.8.5 |
| secure-client | — | — |
References
Exploit Protection
Are you running anyconnect-vpn-client?
CVE-2024-3661 carries CVSS 7.6 High rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.
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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.
