Imperva Web Application Firewall (WAF) before 2021-12-23 allows remote unauthenticated attackers to use "Content-Encoding: gzip" to evade WAF security controls and send malicious HTTP POST requests to web servers behind the WAF.
CVE-2021-45468
CRITICALNVD 9.89.8—Elevated
EchelonGraph scoreMEDIUM confidence
This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 4.0%, top 11% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 4%CVSS: 9.8Exploit: Elevated riskExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 9.8
- EG Score
- 9.8(medium)
- EG Risk
- 65(Track*)EG Risk 65/100SSVC: Track*
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity98% × 45%Exploitation40% × 40%Automatability30% × 15%Action: Watch closely — could escalate to Attend. - EPSS PROB
- 4%
- EPSS %ILE
- 90%
- KEV
- Not listed
Published
January 14, 2022
Last Modified
November 21, 2024
Advisory Details (1)
Auto-updated Sep 19, 2026No patch confirmed yet.
generic
Zero-Day Collaboration With Imperva to Eliminate a… | Bishop Fox
https://bishopfox.com/blog/imperva-eliminates-critical-exposureWeakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Frequently asked(5)
What is CVE-2021-45468?
CVE-2021-45468 is a critical vulnerability published on January 14, 2022. Imperva Web Application Firewall (WAF) before 2021-12-23 allows remote unauthenticated attackers to use "Content-Encoding: gzip" to evade WAF security controls and send malicious HTTP POST requests to web servers behind the WAF.
When was CVE-2021-45468 disclosed?
CVE-2021-45468 was first published in the National Vulnerability Database on January 14, 2022, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-45468 actively exploited?
CVE-2021-45468 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4% probability of exploitation in the next 30 days, which ranks it in the top 10.0% of all scored CVEs.
What is the CVSS score of CVE-2021-45468?
CVE-2021-45468 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2021-45468?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-45468, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2021-45468
Is Your Infrastructure Affected by CVE-2021-45468?
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