CVE-2019-12677

mediumpriority · track · 27EPSS 0.015 · 75 %ileEURUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
1.53% (75th) EPSS
CVSS 4 · medium
Is it mine?
319 products
Check your exposure
Who says so?
4 sources
cnnvd · enisa_euvd · fstec_bdu · cisco_csaf

EPSS · scored 2026-10-27

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.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

7.7
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4–7.7

v2.04mediumAV:N/AC:L/Au:S/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 8 · impact 2.9
v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 2.8 · impact 3.6
v3.07.7highCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU
v3.07.7highCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hsecondary · psirt@cisco.com USexploitability 3.1 · impact 4
v3.07.7highCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hsecondary · Cisco PSIRT US
v3.17.7highAV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU
v3.16mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-755USprimaryCWE-172USCWE-176US
05

affected products (319)

Products and version ranges known to be affected.

showing 20 of 319
06

advisories (1)

Vendor and ecosystem advisories describing this.

  • cisco-sa-20191002-asa-ssl-vpn-dosCisco Adaptive Security Appliance Software SSL VPN Denial of Service Vulnerability2019-10-02csaf · cisco_csafUS

    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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is part of the October 2019 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication, which includes 10 Cisco Security Advisories that describe 18 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: October 2019 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-72541"].

07

also known as (4)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducisco_csafNVDCVE.orgMITRE
published 2019-10-02modified 2026-06-17
10

references (7)

External citations — patches, advisories, analysis.

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