High severity · published Aug 27, 2026
CVE-2026-78009
Fireware OS Out-of-Bounds Read in iked Allows Unauthenticated Denial of Service (DoS)
8.7
CVSS
0.5%
EPSS
No
On KEV
Description
An out-of-bounds read vulnerability in the WatchGuard Fireware OS iked process allows a remote unauthenticated attacker to create a Denial of Service (DoS) condition in VPN processing by sending specially crafted network traffic.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 46% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FO
Fireware OS · WatchGuard
2025.0 before 2026.2.2; 12.0 before 12.12.2; 2026.3 before 2026.3.1; 12.0 before 12.5.20 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-78009
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-78009
psirt.watchguard.com
https://psirt.watchguard.com/CVE-2026-78009
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