What is the CVSS score of CVE-2019-9900?

CVE-2019-9900 has a CVSS 3.1 base score of 8.3 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L. EPSS exploitation probability: 3.7%.

Is there a public PoC exploit available for CVE-2019-9900?

Yes, a public proof-of-concept exploit is available for CVE-2019-9900. Prioritise patching immediately. EPSS: 3.7%.

Envoy CVE-2019-9900

HIGH

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') (CWE-74)

2019-04-25 cve@mitre.org

Authentication Bypass Envoy Openshift Service Mesh

8.3

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

8.3 HIGH

AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

Low

Lifecycle Timeline

CVE Published

Apr 25, 2019 - 15:29 nvd

HIGH 8.3

DescriptionNVD

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.

AnalysisAI

When parsing HTTP/1.x header values, Envoy 1.9.0 and before does not reject embedded zero characters (NUL, ASCII 0x0). Rated high severity (CVSS 8.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified under CWE-74. 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 include: Envoyproxy Envoy, Redhat Openshift Service Mesh.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.