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No exploitation reportedFix available

CVE-2026-18145

Fireware OS Stack-based Buffer Overflow in spamd Allows Remote Code Execution

No exploitation reported by the sources we read.

  • Published2026-09-30
  • Fixed in2026.3.2 · 2026.2.3 · 12.12.3 · 12.5.21
  • WeaknessCWE-121

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A stack-based buffer overflow vulnerability in the spamBlocker (spamd) service of WatchGuard Fireware OS allows an authenticated attacker with administrator privileges to crash the service or potentially execute arbitrary code by sending a specially crafted management request.

Timeline

dates in UTC
  1. 2026-09-3000:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-18145?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-18145?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Watchguard fireware
BranchAffectedFixed in
2026.3≥ 2026.3, < 2026.3.22026.3.2
2026.2≥ 2025.2, < 2026.2.32026.2.3
12.12≥ 12.12, < 12.12.312.12.3
12.x≥ 12.0, < 12.5.2112.5.21

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Watchguard fireware to 2026.3.2 · 2026.2.3 · 12.12.3 · 12.5.21

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CISA-ADPSSVC decisionnone2026-09-30
  • OpenCVESSVC decisionnone—
  • CNACVSS 4.08.6read 2026-10-23
  • NVDCVSS 3.17.2read 2026-10-23
  • CNAweakness (CWE)CWE-121read 2026-10-23
  • FIRST EPSSEPSS score0.4 %2026-10-22

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CVSS 4.0 vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2026-09-30
Last Modified
2026-10-08
NVD status
Analyzed

Frequently asked questions

What is CVE-2026-18145?

A stack-based buffer overflow vulnerability in the spamBlocker (spamd) service of WatchGuard Fireware OS allows an authenticated attacker with administrator privileges to crash the service or potentially execute arbitrary code by sending a specially crafted management request.

Is CVE-2026-18145 actively exploited?

Active exploitation of CVE-2026-18145 has not been confirmed. Its EPSS score was 0.4% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-18145?

CVE-2026-18145 has a CVSS v3 base score of 7.2 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.

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