CVE-2019-12677

Cisco Adaptive Security Appliance Software SSL VPN Denial of Service Vulnerability

MEDIUM

6.5

CVSS Score

Published: October 2, 2019 at 07:06 PM UTC

Updated: June 17, 2026 at 02:15 AM UTC

11 products affected across 1 vendorAdaptive Security ApplianceASA 5580ASA 5505

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Severity

MEDIUM6.5

Exploit prediction

EPSS 2%

SSVC

No known exploit

Description

A vulnerability in the Secure Sockets Layer (SSL) VPN feature of Cisco Adaptive Security Appliance (ASA) Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition that prevents the creation of new SSL/Transport Layer Security (TLS) connections to an affected device. The vulnerability is due to incorrect handling of Base64-encoded strings. An attacker could exploit this vulnerability by opening many SSL VPN sessions to an affected device. The attacker would need to have valid user credentials on the affected device to exploit this vulnerability. A successful exploit could allow the attacker to overwrite a special system memory location, which will eventually result in memory allocation errors for new SSL/TLS sessions to the device, preventing successful establishment of these sessions. A reload of the device is required to recover from this condition. Established SSL/TLS connections to the device and SSL/TLS connections through the device are not affected. Note: Although this vulnerability is in the SSL VPN feature, successful exploitation of this vulnerability would affect all new SSL/TLS sessions to the device, including management sessions.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Adaptive Security Appliance · Cisco

95%

v < 9.1.7.49.2 ≤ v < 9.2.4.89.3 ≤ v < 9.3.3.99.4 ≤ v < 9.4.2.119.5 ≤ v < 9.5.2.59.6 ≤ v < 9.6.2

Affected range stops below 9.1.7.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 9.2.4.8, so it looks safe — our inference, not a vendor statement

Affected range stops below 9.3.3.9, so it looks safe — our inference, not a vendor statement

Affected range stops below 9.4.2.11, so it looks safe — our inference, not a vendor statement

Affected range stops below 9.5.2.5, so it looks safe — our inference, not a vendor statement

Affected range stops below 9.6.2, so it looks safe — our inference, not a vendor statement

cisco-asa-5505 (environment) · cisco-asa-5510 (environment) · cisco-asa-5512-x (environment) · cisco-asa-5515-x (environment) · cisco-asa-5520 (environment) · cisco-asa-5525-x (environment) · cisco-asa-5550 (environment) · cisco-asa-5555-x (environment) · cisco-asa-5580 (environment) · cisco-asa-5585-x (environment)

ASA 5505 · Ciscodevice

80%

All versions

ASA 5510 · Ciscodevice

80%

All versions

Asa 5512-X · Ciscodevice

80%

All versions

Asa 5515-X · Ciscodevice

80%

All versions