CVE-2026-20242: A vulnerability in the External Database Access feature of Cisco Secure Firewall Management Center (FMC) Softw

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CRITICAL 9.8REMOTE

CVE-2026-20242 is a critical-severity flaw (CVSS 9.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability in the External Database Access feature of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to execute arbitrary commands as root on an affected device. This vulnerability is due to insecure deserialization of a user-supplied Java byte stream from a host that is configured in the external database access list. An attacker could exploit this vulnerability by sending a cr

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.9% (top 41%)
CISA exploited list	No
Weakness	CWE-502
Published	2026-09-16
Last modified	2026-09-18

Publisher (CNA): Cisco Systems, Inc.

Last updated 2026-09-18 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-09-16 20:17 UTCPublished CVE record published
2026-09-18 04:17 UTCUpdated Record last modified

Exact fixes by distribution

Fedora 46 · icecat · FIXED · 153.6.0-2.rh1.fc46 · FEDORA-2026-25e05b5320 · source

sudo dnf upgrade --advisory=FEDORA-2026-25e05b5320

Fedora ELN · edk2 · FIXED · 20260812-14.eln159 · FEDORA-2026-8850ef9153 · source

sudo dnf upgrade --advisory=FEDORA-2026-8850ef9153

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-20242?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-20242 being exploited?

CVE-2026-20242 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-20242 affect?

CVE-2026-20242 affects affected software. Severity is critical (CVSS 9.8). A vulnerability in the External Database Access feature of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to execute arbitrary commands as root on an affected device. This vuln

How urgent is CVE-2026-20242?

Priority 57/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

Software pages

Java vulnerabilities · Cisco vulnerabilities

References

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