8.7

CVE-2026-78009: Fireware OS Out-of-Bounds Read in iked Allows Unauthenticated Denial of Service (DoS)

Deferred
Published 27-08-2026Last modified 03-09-2026

Vulnerability summary

CVE-2026-78009 is a high (CVSS 8.7) Improper Input Validation vulnerability in watchguard fireware os. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 44.9% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.7/10
010
High · v4.0 (CVE.org)
EPSS score
0.54%
0%100%
Low · +0.22 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 27-08-2026
    PublishedVulnerability first disclosed.
  2. 03-09-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.54%

Chance of exploitation in the next 30 days

Percentile

45%

Versus all other CVEs

30-day change

Increase +0.22 pp

From 0.32% on 22-09-2026

22-09-202622-10-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Watchguard1 product
  • fireware os≥ 2025.0, < 2026.2.2 | ≥ 12.0, < 12.12.2 | ≥ 2026.3, < 2026.3.1 | ≥ 12.0, < 12.5.20

1 vendor · 1 product

References

1 links