GitHub Advisoryadvisory · Go
GHSA-mf24-chxh-hmvj Envoy Gateway Log Injection Vulnerability
MEDIUM
Official page ↗
- Aliases
- CVE-2025-25294
- Ecosystem
- Go
- Packages
- github.com/envoyproxy/gateway
- Severity
- Moderate
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- Weaknesses
- CWE-117
- Reviewed
- 2025-03-06
Affected packages
• Go github.com/envoyproxy/gateway: < 1.2.7 → fixed in 1.2.7
• Go github.com/envoyproxy/gateway: >= 1.3.0-rc.1, < 1.3.1 → fixed in 1.3.1
Description
Impact
In all Envoy Gateway versions prior to 1.2.7 and 1.3.1 a default Envoy Proxy access log configuration is used. This format is vulnerable to log injection attacks.
If the attacker uses a specially crafted user-agent which performs json injection, then he could add and overwrite fields to the access log.
Examples of attacks include:
• Using following string as user agent : `HELLO-WORLD", "evil-ip": "1.1.1.1", "x-forwarded-for": "1.1.1.1` would lead to setting of new access log properties and overwrite of existing properties. Existing properties such as the value of the X-Forwarded-For header may have importance for security analysis of access logs, and their overwrite can be used to hide malicious activity.
• Using the following string as user-agent : `"` which renders an invalid json document. The invalid document may fail to be processed by observability solutions, which would allow attacker to hide malicious activity.
Patches
1.3.1, 1.2.7
Fix
Using JSON format as the default format for access logs. The logged document will contain the same key and values as before. Only the order of properties is different inside the logged document.
Workaround
One can overwrite the old text based default format with JSON formatter by setting the following property:
"EnvoyProxy.spec.telemetry.accessLog" to
```
settings:
• format:
type: JSON
json:
start_time: '%START_TIME%'
method: '%REQ(:METHOD)%'
x-envoy-origin-path: '%REQ(X-ENVOY-ORIGINAL-PATH?:PATH)%'
protocol: '%PROTOCOL%'
response_code: '%RESPONSE_CODE%'
response_flags: '%RESPONSE_FLAGS%'
response_code_details: '%RESPONSE_CODE_DETAILS%'
connection_termination_details: '%CONNECTION_TERMINATION_DETAILS%'
upstream_transport_failure_reason: '%UPSTREAM_TRANSPORT_FAILURE_REASON%'
bytes_received: '%BYTES_RECEIVED%'
bytes_sent: '%BYTES_SENT%'
duration: '%DURATION%'
x-envoy-upstream-service-time: '%RESP(X-ENVOY-UPSTREAM-SERVICE-TIME)%'
x-forwarded-for: '%REQ(X-FORWARDED-FOR)%'
user-agent: '%REQ(USER-AGENT)%'
x-request-id: '%REQ(X-REQUEST-ID)%'
:authority: '%REQ(:AUTHORITY)%'
upstream_host: '%UPSTREAM_HOST%'
upstream_cluster: '%UPSTREAM_CLUSTER%'
upstream_local_address: '%UPSTREAM_LOCAL_ADDRESS%'
downstream_local_address: '%DOWNSTREAM_LOCAL_ADDRESS%'
downstream_remote_address: '%DOWNSTREAM_REMOTE_ADDRESS%'
requested_server_name: '%REQUESTED_SERVER_NAME%'
route_name: '%ROUTE_NAME%'
```
see API definition here
References
_Are there any links users can visit to find out more?_
Related
Alias · CVE (1)
- CVE-2025-25294 Envoy Gateway is an open source project for managing Envoy Proxy as a standalone or Kubernetes-based application gateway. vulnerability
Weakness · CWE (1)
- CWE-117 Improper Output Neutralization for Logs weakness
References
- https://github.com/envoyproxy/gateway/security/advisories/GHSA-mf24-chxh-hmvj web
- https://nvd.nist.gov/vuln/detail/CVE-2025-25294 advisory
- https://github.com/envoyproxy/gateway/commit/041d474a70d5921e5d65e6e14ea60e14dac70b01 web
- https://github.com/envoyproxy/gateway/commit/358bed50dcb7b32f39a2edb252fb1399c7fc65dc web
- https://github.com/envoyproxy/gateway/commit/8f48f5199cf1bbb9a8ac0695c5171bfef6c9198a web
- https://github.com/envoyproxy/gateway package
- https://github.com/envoyproxy/gateway/releases/tag/v1.2.7 web
- https://github.com/envoyproxy/gateway/releases/tag/v1.3.1 web
- https://pkg.go.dev/vuln/GO-2025-3504 web