Is CVE-2026-121823 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-121823 being exploited in the wild.

How severe is CVE-2026-121823?

Informational severity, published 6 November 2026.

Which products and versions are affected?

LINE Armeria < 1.43.0 (from 1.13 onwards).

Is there a fix for CVE-2026-121823?

Yes: fixed in 1.43.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-121823 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-121823?

Check whether you run LINE Armeria at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-121823: LINE Armeria path normalization auth bypass

Q: Which products and versions are affected?

LINE Armeria < 1.43.0 (from 1.13 onwards).

Q: Is there a fix for CVE-2026-121823?

Yes: fixed in 1.43.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-121823 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-121823?

Check whether you run LINE Armeria at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-121823 · Severity: info · Published 2026-11-06

Armeria is a Java web framework that handles HTTP requests and serves files. The framework fails to properly normalize certain path segments (like /./) when checking access controls, allowing attackers to bypass authentication and access protected resources without permission. This affects servers that use Armeria's path-based decorators or file services to protect sensitive areas.

Technologies: LINE Armeria. Vendors: LINE.

Quick answers

Is CVE-2026-121823 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-121823 being exploited in the wild.
How severe is CVE-2026-121823?: Informational severity, published 6 November 2026.
Which products and versions are affected?: LINE Armeria < 1.43.0 (from 1.13 onwards).
Is there a fix for CVE-2026-121823?: Yes: fixed in 1.43.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-121823 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-121823?: Check whether you run LINE Armeria at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: 1.43.0

Technical details

The vulnerability stems from inconsistent path normalization: Armeria's request routing rejects .. but preserves . and %2e-decoded path segments, while underlying file systems (FileService, TomcatService, JettyService) normalize these away. An attacker can request /./ or /%2e/ prefixed paths to bypass decoratorUnder("/admin") checks that rely on string prefix matching. The flaw affects all versions from 1.13 through 1.42.0 and is exploitable remotely without authentication or user interaction.

Affected products

LINE Armeria < 1.43.0 (from 1.13 onwards)

Timeline

2026-11-06: disclosed: Advisory published
2026-11-06: patched: Version 1.43.0 released with fix

References

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