Stack buffer overflow in WAD

unknownCVE-2026-71407

CVSSv3 Score: 5.1 A Stack-based Buffer Overflow vulnerability [CWE-121] in FortiOS explicit proxy may allow an unauthenticated attacker who can bypass stack protection and ASLR to execute arbitrary code or commands in the context of the WAD daemon via crafted sockets, only if the explicit proxy is configured with Kerberos authentication and SOCKS enabled. Revised on 2026-08-12 00:00:00

CSIRTS triage

vendor: Fortinet product: FortiOS Memory corruption Remote code execution

What: Stack buffer overflow in FortiOS explicit proxy WAD daemon allows arbitrary code execution under specific configuration conditions.
Who is affected: FortiOS explicit proxy deployments configured with Kerberos authentication and SOCKS enabled.
Urgency: Moderate urgency; CVSS 5.1 requires specific configuration and stack protection bypass, limiting exposure.
Action: Update FortiOS to patch CVE-2026-71407 and disable Kerberos+SOCKS explicit proxy if not required.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Fortinet FortiGuard PSIRT (INTL · vendor-psirt · site)
Severity: unknown
Published: 2026-08-12
Exploitation: Not in CISA KEV at last sync

Original advisory: https://fortiguard.fortinet.com/psirt/FG-IR-26-161

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-714070.49% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 40% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-71407	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

medium[NEW] [medium] Fortinet FortiOS: Multiple vulnerabilities enable code execution and DoScert-bund
unknownFortinet Products Multiple Vulnerabilitieshkcert
unknownMultiple vulnerabilities in Fortinet products (August 13, 2026)cert-fr-avis
mediumCVE-2026-71407: A Stack-based Buffer Overflow vulnerability [CWE-121] vulnerability in Fortinet FortiOS 7.6.1 …nvd

Recent advisories for Stack buffer overflow

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

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mediumCVE-2026-16692: IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to cause a denial of …nvd · 2026-08-13