Skip to main content
VulnerabilityPublished

CVE-2026-20135: CWE-415

Source GCVE Database

0
Compare
Authoritative record:CVE-2026-20135· High 8.6

Not known to be exploited · CVSS 8.6 High.

Data as of 31 Oct 2026, 20:20 UTC

CVSS 3.1 base score
8.6High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.6% chance of exploitation in 30 days – higher than 51% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 16 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 31 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
CiscoCisco Secure Firewall Threat Defense (FTD) SoftwareAffected
  • 7.0.0 – 7.7.11
58 affected builds
Fixed in–

AI-suggested

Until a patch is available, monitor for unusual TLS 1.3 traffic and consider limiting exposure of TLS 1.3-enabled listening sockets if feasible.

Description

A vulnerability in the TLS 1.3 implementation of Cisco Secure Firewall Threat Defense (FTD) Software allows an unauthenticated remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS). The issue arises from improper buffer management during TLS 1.3 connections. Exploitation involves sending a crafted TLS 1.3 packet to a TLS 1.3-enabled listening socket, causing the LINA process to crash and the device to reload either before or after connection authentication.

References

Community reviews

Loading reviews…