CVE-2019-1687

highpriority · track · 31EPSS 0.029 · 87 %ileEURUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

2.93% (87th) EPSS

CVSS 7.8 · high

Is it mine?

19 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · cisco_csaf

EPSS · scored 2026-10-27

A vulnerability in the TCP proxy functionality for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to restart unexpectedly, resulting in a denial of service (DoS) condition. The vulnerability is due to an error in TCP-based packet inspection, which could cause the TCP packet to have an invalid Layer 2 (L2)-formatted header. An attacker could exploit this vulnerability by sending a crafted TCP packet sequence to the targeted device. A successful exploit could allow the attacker to cause a DoS condition.

remediations

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

A vendor fix is available.

FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Softwarecisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco Secure Firewall Threat Defense (FTD) Softwarecisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com

cvss

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

7.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.8–7.8

v2.07.8highAV:N/AC:L/Au:N/C:N/I:N/A:Cprimary · NVD / NIST USexploitability 10 · impact 6.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.06.8mediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU

v3.06.8mediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · psirt@cisco.com USexploitability 2.2 · impact 4

v3.06.8mediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · Cisco PSIRT US

v3.16.8mediumAV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

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

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-20USprimaryCWE-20US

affected products (19)

Products and version ranges known to be affected.

Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Softwareall versionscisco_csafUS
Cisco Cisco Secure Firewall Threat Defense (FTD) Softwareall versionscisco_csafUS
Cisco Cisco Adaptive Security Appliance (ASA) Softwareunspecified → 9.4.4.34enisa_euvdEU
Cisco Cisco Adaptive Security Appliance (ASA) Softwareunspecified → 9.8.4enisa_euvdEU
Cisco Cisco Adaptive Security Appliance (ASA) Softwareunspecified → 9.9.2.50enisa_euvdEU
Cisco Systems Inc. Adaptive Security Appliance≤ 9.4.4.34fstec_bduRU
Cisco Systems Inc. Adaptive Security Appliance9.10 → 9.10.1.17fstec_bduRU
Cisco Systems Inc. Adaptive Security Appliance9.5 → 9.6.4.25fstec_bduRU
Cisco Systems Inc. Adaptive Security Appliance9.7 → 9.8.4fstec_bduRU
Cisco Systems Inc. Adaptive Security Appliance9.9 → 9.9.2.50fstec_bduRU
Cisco Systems Inc. Firepower Threat Defense6.0 → 6.2.3.12fstec_bduRU
Cisco Systems Inc. Firepower Threat Defense6.3.0 → 6.3.0.3fstec_bduRU
cisco adaptive security appliance software< 9.4.4.34nvdUScpe:2.3:a:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
cisco adaptive security appliance software9.10 → 9.10.1.17nvdUScpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
cisco adaptive security appliance software9.5 → 9.6.4.25nvdUScpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
cisco adaptive security appliance software9.7 → 9.8.4nvdUScpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
cisco adaptive security appliance software9.9 → 9.9.2.50nvdUScpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
cisco secure firewall threat defense6.0.0 → 6.2.3.12nvdUScpe:2.3:a:cisco:secure_firewall_threat_defense:*:*:*:*:*:*:*:*
cisco secure firewall threat defense6.3.0 → 6.3.0.3nvdUScpe:2.3:a:cisco:secure_firewall_threat_defense:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

cisco-sa-20190501-asa-ftdtcp-dosCisco Adaptive Security Appliance Software and Firepower Threat Defense Software TCP Proxy Denial of Service Vulnerability2019-05-01csaf · cisco_csafUS
A vulnerability in the TCP proxy functionality for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to restart unexpectedly, resulting in a denial of service (DoS) condition. The vulnerability is due to an error in TCP-based packet inspection, which could cause the TCP packet to have an invalid Layer 2 (L2)-formatted header. An attacker could exploit this vulnerability by sending a crafted TCP packet sequence to the targeted device. A successful exploit could allow the attacker to cause a DoS condition. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cisco_csaf nvd NVD CVE.org MITRE

published 2019-05-03modified 2026-08-11

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references (12)

External citations — patches, advisories, analysis.

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