What’s Vulnerable › Vulnerabilities

CVE-2019-9901

• Severity: critical (CVSS 10.0 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 5.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2019-04-25 · updated 2026-06-17
• Weakness: CWE-706

Description

Envoy 1.9.0 and before does not normalize HTTP URL paths. A remote attacker may craft a relative path, e.g., something/../admin, to bypass access control, e.g., a block on /admin. A backend server could then interpret the non-normalized path and provide an attacker access beyond the scope provided for by the access control policy.

Affected products

• envoyproxy envoy: through 1.9.0

References

• https://github.com/envoyproxy/envoy/issues/6435
• https://github.com/envoyproxy/envoy/security/advisories/GHSA-xcx5-93pw-jw2w
• https://groups.google.com/forum/#%21topic/envoy-announce/VoHfnDqZiAM
• https://www.envoyproxy.io/docs/envoy/v1.9.1/intro/version_history
• https://github.com/envoyproxy/envoy/issues/6435
• https://github.com/envoyproxy/envoy/security/advisories/GHSA-xcx5-93pw-jw2w
• https://groups.google.com/forum/#%21topic/envoy-announce/VoHfnDqZiAM
• https://www.envoyproxy.io/docs/envoy/v1.9.1/intro/version_history

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