Vulnerability in Envoyproxy Envoy
CVE-2019-9900
When parsing HTTP/1.x header values, Envoy 1.9.0 and before does not reject embedded zero characters (NUL, ASCII 0x0). This allows remote attackers crafting header values containing embedded NUL characters to potentially bypass header matching rules, gaining access to unauthorized resources.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L.
EPSS exploit prediction
EPSS: 0.037 (89.7th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 90th percentile — 89.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.037 · newest: 0.037 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- access.redhat.com/errata/RHSA-2019:0741 (vendor-advisory, Third Party Advisory)
- www.envoyproxy.io/docs/envoy/v1.9.1/intro/version_history (Release Notes, Vendor Advisory)
- github.com/envoyproxy/envoy/issues/6434 (Exploit, Third Party Advisory, Issue Tracking)
- groups.google.com/forum/
- github.com/envoyproxy/envoy/security/advisories/GHSA-x74r-f4mw-c32h (Exploit, Third Party Advisory, Mitigation)
Frequently asked questions
- What is CVE-2019-9900?
- CVE-2019-9900 is a high-severity vulnerability in Envoyproxy Envoy, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 8.3/10. Published 2019-04-25.
- How severe is CVE-2019-9900?
- High severity. CVSS v3 base score is 8.3 out of 10.
- Is CVE-2019-9900 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.