CVE-2026-54665
MEDIUM 6.3Apache NiFi 0.0.1 through 2.9.0 support building qualified URLs from one of several HTTP request headers that provide an alternative to the standard Host header without validating the values provided. Apache NiFi 1.6.0 introduced a configurable application property to restrict values provided in the HTTP Host header, but did not apply the validation to alternative Proxy and Forwarded headers. The absence of proxy host header validation allowed a client to instruct Apache NiFi web services to construct invalid qualified URLs for redirection or data references. Upgrading to Apache NiFi 2.10.0 is the recommended mitigation, which implements validation for the X-ProxyHost and X-Forwarded-Host HTTP request headers based on the nifi.web.proxy.host property. Enabling header validation requires configuring the application with HTTPS. Reverse proxy servers in front of Apache NiFi are responsible for filtering input request headers and providing allowed values to the application.
No known exploitation, public exploit, or elevated probability at this time. Track for changes.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 19th percentile
Impact if exploited
6.3CVSS 4.0 · MEDIUM
- ConfidentialityNone
- IntegrityLow
- AvailabilityNone
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
- ⚠Requirements: Specific conditions must be present
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-54665/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-54665/poc.json
Weakness (CWE)
- CWE-346: Origin Validation Error
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/S:N/AU:Y/R:A/V:D/RE:L/U:Green
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Apache | Nifi | ≥ 0.0.1 and < 2.10.0 |
All CVSS metrics
- MEDIUM 6.3 v4.0 · CNA Primary
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/S:N/AU:Y/R:A/V:D/RE:L/U:Green - MEDIUM 6.3 v4.0 · NVD Secondary
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/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:N/AU:Y/R:A/V:D/RE:L/U:Green - MEDIUM 5.3 v3.1 · NVD Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N