Skip to main content
VulnerabilityPublished

CVE-2026-20341: Deserialization of Untrusted Data

Source GCVE Database

0
Compare
Authoritative record:CVE-2026-20341· Critical 9.1

Not known to be exploited · CVSS 9.1 Critical.

Data as of 31 Oct 2026, 20:20 UTC

CVSS 3.1 base score
9.1Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/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 Management Center (FMC)Affected
  • 7.0.0 – 10.0.1
68 affected builds
Fixed in–

AI-suggested

Since exploitation requires valid administrative credentials, limiting administrative access and monitoring for suspicious activity on managed Cisco FTD devices is advisable until an official fix is available.

Description

A critical vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software allows an authenticated remote attacker with administrative credentials to gain root privileges. The flaw arises from unsecured deserialization of untrusted data over the sftunnel management connection. Exploitation requires sending crafted remote procedure calls (RPCs) via sftunnel. This vulnerability affects devices running Cisco Secure FMC Software and its high-availability peers.

References

Community reviews

Loading reviews…