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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…
Medium6.5EPSS 3.7%
- Published
- Updated
- Reserved
- Assigned by
- mitre
Description
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| mitreCNA (assigner) | 3.0 | Medium6.5 | CVSS:3.0/AC:H/AV:N/A:L/C:L/I:L/PR:N/S:C/UI:N |
| NVDNVD · Modified | 3.1 | High8.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L |
- EPSS (exploitation in 30 days)
- 3.7% · top 10% of all CVEs (5 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Weakness
Affected products
n/a
- affected n/a
References (5)
- RHSA-2019:0741 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- https://www.envoyproxy.io/docs/envoy/v1.9.1/intro/version_history (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/envoyproxy/envoy/issues/6434 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://groups.google.com/forum/#%21topic/envoy-announce/VoHfnDqZiAM (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-x74r-f4mw-c32h (opens in a new tab)x_refsource_CONFIRMx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2019-9900)Record last updated .