Content-Encoding WAF Evasion

unknownCVE-2026-70466

CVSSv3 Score: 4.8 An incomplete list of disallowed inputs [CWE-184] in FortiWeb WAF may allow an unauthenticated attacker to bypass policies via specifically crafted requests. Revised on 2026-08-12 00:00:00

CSIRTS triage

vendor: Fortinet product: FortiWebMisconfiguration

What: Incomplete input validation in FortiWeb WAF allows attackers to bypass security policies via content-encoding evasion.
Who is affected: FortiWeb WAF deployments relying on policy enforcement.
Urgency: Moderate urgency; CVSS 4.8 compromises WAF effectiveness but does not directly enable code execution.
Action: Update FortiWeb to patch CVE-2026-70466 and review WAF policy coverage for encoding bypasses.

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-26-157

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-2026-704660.31% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 24% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-70466	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

unknownNCSC-2026-0300 [1.00] [M/H] Vulnerabilities patched in Fortinet FortiWebncsc-nl
high[NEW] [high] Fortinet FortiWeb: Multiple vulnerabilities enable bypass of security measurescert-bund
unknownFortinet Products Multiple Vulnerabilitieshkcert
unknownMultiple vulnerabilities in Fortinet products (August 13, 2026)cert-fr-avis
mediumCVE-2026-70466: A incomplete list of disallowed inputs vulnerability in Fortinet FortiWeb 8.0.0 through 8.0.2,…nvd