CVE-2021-43795: Armeria Armeria Vulnerability
HIGHCVE-2021-43795 is a HIGH (CVSS 7.5) armeria vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting Armeria libraries in the Maven ecosystem. The issue involves armeria. Remediation is available by upgrading affected packages to version 1.13.4.
CVE-2021-43795 at a Glance
Security Impact
CVSS: 7.5
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).
How to Fix CVE-2021-43795
To remediate this vulnerability, upgrade all affected Armeria dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
<dependency>
<groupId>com.linecorp.armeria</groupId>
<artifactId>armeria</artifactId>
<version>1.13.4</version>
</dependency>Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:tree -Dincludes=com.linecorp.armeriaHow to Check if You Are Affected
To determine whether your Java application is affected by CVE-2021-43795, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:tree -Dincludes=com.linecorp.armeriaAnalyze the terminal output to locate any version of Armeria in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.13.4), your application is affected.
Note: The mvn dependency:tree -Dincludes=com.linecorp.armeria command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. In Armeria, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2021-43795 Affected Armeria Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
com.linecorp.armeria:armeria
|
Maven |
≥ 1.12.0
< 1.13.4
|
1.13.4
|
References
Frequently Asked Questions
What is CVE-2021-43795?
Which Armeria versions are affected?
What version fixes CVE-2021-43795?
Is armeria affected?
What is the CVSS score of CVE-2021-43795?
What CWE is associated with CVE-2021-43795?
How can I check Maven dependencies for CVE-2021-43795?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-8fp4-rp6c-5gcv",
"modified" : "2021-12-02T21:28:29Z",
"published" : "2021-12-02T22:25:54Z",
"aliases" : [ "CVE-2021-43795" ],
"summary" : "Path Traversal in com.linecorp.armeria:armeria",
"details" : "### Impact\n\nAn attacker can access an Armeria server's local file system beyond its restricted directory by sending an HTTP request whose path contains `%2F` (encoded `/`), such as `/files/..%2Fsecrets.txt`, bypassing Armeria's path validation logic.\n\n### Patches\n\nArmeria 1.13.4 or above contains the hardened path validation logic that handles `%2F` properly. \n\n### Workarounds\n\nThis vulnerability can be worked around by inserting a decorator that performs an additional validation on the request path, e.g.\n\n```java\nServer\n .builder()\n .serviceUnder(\n \"/files\",\n FileService\n .of(...)\n .decorate((delegate, ctx, req) -> {\n String path = req.headers().path();\n if (path.contains(\"%2f\") || path.contains(\"%2F\")) {\n return HttpResponse.of(HttpStatus.BAD_REQUEST);\n }\n return delegate.serve(ctx, req);\n })\n )\n .build()\n```\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n* Open an issue in [line/armeria](https://github.com/line/armeria)\n* Chat with us at [Slack](https://armeria.dev/s/slack)\n\n### Credits\n\nThis vulnerability was originally reported by Abdallah Zaher ([elcayser-0x0a](https://hackerone.com/elcayser-0x0a?type=user)).",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Maven",
"name" : "com.linecorp.armeria:armeria"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "1.12.0"
}, {
"fixed" : "1.13.4"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/line/armeria/security/advisories/GHSA-8fp4-rp6c-5gcv"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-43795"
}, {
"type" : "WEB",
"url" : "https://github.com/line/armeria/pull/3855"
}, {
"type" : "WEB",
"url" : "https://github.com/line/armeria/commit/e2697a575e9df6692b423e02d731f293c1313284"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/line/armeria"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-22" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2021-12-02T21:28:29Z",
"nvd_published_at" : "2021-12-02T18:15:00Z"
}
}