istio/envoy: Authorization bypass via null characters injection in HTTP/1.x
Published Apr 25, 2019
8.3
HIGHCVSS 3.1
EPSS 3.73%
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.
Affected products
No data.
Configuration 1
- ≤ 1.9.0
Configuration 2
- n/a
No data.
OpenShift Service Mesh Tech Preview
servicemesh-proxy-0:0.9.1-1.el7
Fixed · RHSA-2019:0741
| Product | Package | State | Advisory |
|---|---|---|---|
| OpenShift Service Mesh Tech Preview | servicemesh-proxy-0:0.9.1-1.el7 | Fixed | RHSA-2019:0741 |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:L
2 other sources (MITRE, Red Hat) ▾
CVSS:3.0/AC:H/AV:N/A:L/C:L/I:L/PR:N/S:C/UI:N
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
AV:N/AC:L/Au:N/C:P/I:P/A:P
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (15 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 3.73% (0.03732) | 89.48th | v5 (v2026.06.15) |
| Jun 15, 2026 | 3.73% (0.03732) | 88.37th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.05% (0.00046) | 11.50th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.49% (0.00488) | 76.85th | v3 (v2023.03.01) |
| Apr 18, 2024 | 0.45% (0.00448) | 74.75th | v3 (v2023.03.01) |
| Feb 8, 2024 | 0.50% (0.00504) | 75.77th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.50% (0.00504) | 72.80th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.21% (0.01213) | 66.61th | v2 (v2022.01.01) |
| Feb 17, 2023 | 1.21% (0.01213) | 66.22th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.21% (0.01213) | 64.21th | v2 (v2022.01.01) |
| Feb 4, 2022 | 7.18% (0.07176) | 80.33th | v2 (v2022.01.01) |
| Feb 3, 2022 | 6.66% (0.06657) | 83.16th | v1 |
| Jan 6, 2022 | 6.66% (0.06657) | 83.00th | v1 |
| Sep 1, 2021 | 1.57% (0.01565) | 73.12th | v1 |
| Apr 14, 2021 | 1.57% (0.01565) | 0.00th | v1 |
References (9)
- https://access.redhat.com/errata/RHSA-2019:0741 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/security/cve/CVE-2019-9900 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1698020 Issue Tracking
- https://github.com/envoyproxy/envoy/issues/6434 x_refsource_CONFIRMExploitIssue TrackingThird Party Advisory
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-x74r-f4mw-c32h x_refsource_CONFIRMExploitMitigationThird Party Advisory
- https://groups.google.com/forum/#%21topic/envoy-announce/VoHfnDqZiAM x_refsource_CONFIRM
- https://nvd.nist.gov/vuln/detail/CVE-2019-9900
- https://www.cve.org/CVERecord?id=CVE-2019-9900
- https://www.envoyproxy.io/docs/envoy/v1.9.1/intro/version_history x_refsource_CONFIRMRelease NotesVendor Advisory
| Link | Providers | Tags |
|---|---|---|
| https://access.redhat.com/errata/RHSA-2019:0741 | vendor-advisoryx_refsource_REDHATThird Party Advisory | |
| https://access.redhat.com/security/cve/CVE-2019-9900 | Vendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=1698020 | Issue Tracking | |
| https://github.com/envoyproxy/envoy/issues/6434 | x_refsource_CONFIRMExploitIssue TrackingThird Party Advisory | |
| https://github.com/envoyproxy/envoy/security/advisories/GHSA-x74r-f4mw-c32h | x_refsource_CONFIRMExploitMitigationThird Party Advisory | |
| https://groups.google.com/forum/#%21topic/envoy-announce/VoHfnDqZiAM | x_refsource_CONFIRM | |
| https://nvd.nist.gov/vuln/detail/CVE-2019-9900 | ||
| https://www.cve.org/CVERecord?id=CVE-2019-9900 | ||
| https://www.envoyproxy.io/docs/envoy/v1.9.1/intro/version_history | x_refsource_CONFIRMRelease NotesVendor Advisory |
Change history (0)
No recorded changes yet.