Home/CVE/Armeria is an open source microservice framework. In affected versions an attacker can access an Armeria server's local
CVE

CVE-2021-43795

Armeria is an open source microservice framework. In affected versions an attacker can access an Armeria server's local

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.

HIGH · CVSS 7.5 EPSS 0.00754
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
Look this up elsewhere - one-click external pivots
NVDCVE.orgCISAVulnersExploit-DBGitHub PoCVulnCheck KEVGreyNoise
▸ How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2021-43795, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
◆

ATT&CK techniques

1

Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.

T1190 · Exploit Public-Facing Application
▤ Build a SIEM detection for these techniques
▤

CAPEC attack patterns

5

Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.

CAPEC-CAPEC-126 · Path Traversal CAPEC-CAPEC-64 · Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-CAPEC-76 · Manipulating Web Input to File System Calls CAPEC-CAPEC-78 · Using Escaped Slashes in Alternate Encoding CAPEC-CAPEC-79 · Using Slashes in Alternate Encoding
⬡

Weakness Classification

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
▤

Affected Products & Versions

1
linecorp armeria< 1.13.4
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Maven com.linecorp.armeria:armeria HIGH fixed in 1.13.4
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · [email protected]
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD02 Dec 2021 · 06:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/line/armeria/commit/e2697a575e9df6692b423e02d731f293c1313284PatchThird Party Advisory
https://github.com/line/armeria/pull/3855Third Party Advisory
https://github.com/line/armeria/security/advisories/GHSA-8fp4-rp6c-5gcvThird Party Advisory
SOC and Response
CVE triage
Stack monitoring
Am I affected
IOC triage
KEV catalog
Recently exploited
Daily brief
Change tracking
Detection Engineering
Coverage workspace
Detection coverage
Coverage check
Telemetry ceiling
SIEM query builder
Sigma rules
SIEM rules
YARA rules
Network rules
D3FEND
Threat Hunting
Threat actors
ATT&CK techniques
Attack paths
Indicators
Atomic tests
Red Team and Pentest
Exploitability triage
Recon pack
Attack paths
CAPEC patterns
Adversary emulation
Compliance and GRC
Framework mapping
Control assessment
Audit view
Coverage report
Atlas Search Threat actors Techniques Tools & malware CWE CAPEC KEV catalog Package vulns
About All capabilities Pricing API docs Live status Privacy policy Terms of service
threatengine.sh