How severe is CVE-2021-43795?

CVE-2021-43795 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-43795?

CVE-2021-43795 affects the following packages: com.linecorp.armeria:armeria (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-43795?

Update com.linecorp.armeria:armeria to 1.13.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-43795 is resolved across your whole dependency graph.

How do I detect CVE-2021-43795 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.linecorp.armeria:armeria. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2021-43795 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2021-43795?

O3 pinpoints whether CVE-2021-43795 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2021-43795 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-43795 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-43795?

CVE-2021-43795 has an EPSS (Exploit Prediction Scoring System) score of 1.6%, placing it in the 73th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2021-43795 published, and has it been updated?

CVE-2021-43795 was published on December 2, 2021 and was last updated on April 11, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

CVE-2021-43795

HIGH

Path Traversal in com.linecorp.armeria:armeria

Also known asGHSA-8fp4-rp6c-5gcv

Published

Dec 2, 2021

Updated

Apr 11, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

1.6%probability of exploitation in next 30 days

Lower Risk73th percentile+0.88%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

☕com.linecorp.armeria:armeria

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Armeria is an open source microservice framework. In affected versions an 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. Armeria 1.13.4 or above contains the hardened path validation logic that handles %2F properly. This vulnerability can be worked around by inserting a decorator that performs an additional validation on the request path.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`com.linecorp.armeria:armeria`	≥ 1.12.0&&< 1.13.4	1.13.4

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.linecorp.armeria:armeria. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update com.linecorp.armeria:armeria to 1.13.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-43795 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2021-43795 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2021-43795. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Armeria is an open source microservice framework. In affected versions an 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. Armeria 1.13.4 or above contains the hardened path validation logic that handles `%2F` properly. This vulnerability can be worked around by inserting a decorator that performs an additional validation on the request path.

O3 Security · Impact-Aware SCA

Is CVE-2021-43795 in your dependencies?

O3 detects CVE-2021-43795 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works