6.9

CVE-2026-13371: watchguard fireware Deserialization of Untrusted Data

CVSS: 6.9v4.0MediumAnalyzed
Published 02-07-2026Last modified 27-08-2026
Open JSON

Vulnerability summary

CVE-2026-13371 is a medium (CVSS 6.9) Deserialization of Untrusted Data vulnerability in watchguard fireware. EPSS estimates a 0.59% chance of exploitation in the next 30 days, higher than 47.3% of scored vulnerabilities.

Overall risk
28/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.9/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.59%
0%100%
Low · +0.24 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 02-07-2026
    PublishedVulnerability first disclosed.
  2. 27-08-2026
    Last modifiedVulnerability information updated.

Description

An authenticated administrator can trigger a denial-of-service condition in the Fireware Management Web UI by sending malformed or crafted data to the put_data endpoint, which performs unsafe deserialization of the attacker-supplied input.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

0.59%

Chance of exploitation in the next 30 days

Percentile

47%

Versus all other CVEs

30-day change

+0.24 pp

From 0.35% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.59%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Watchguard2 products
  • fireware≥ 2025.1, < 2026.2.1 | ≥ 12.5, < 12.5.19 | ≥ 12.0, < 12.12.1
  • fireware os≥ 2025.1, < 2026.2.1 | ≥ 12.0, < 12.12.1 | ≥ 12.0, < 12.11.9 | ≥ 12.0, < 12.5.19

1 vendor · 2 products

References

2 links