CVE-2026-121821LY Corporation Armeria vulnerability
CVE-2026-121821 is a vulnerability in LY Corporation Armeria, rated medium (5.3 on CVSS 4.0).
Why this priority: A public proof of concept exists and exploitation can be automated.
Published · Updated · NVD status: Deferred
What it is
The record does not classify the weakness yet; the description below says what the reporter found.
How it is reached
An attacker can exploit it over the network, without an account, but someone has to act first, such as opening a file or following a link.
What an attacker gains
The direct impact is limited: partial access to data or a partial outage.
Is it being exploited?
CISA's SSVC assessment notes a public proof of concept. It can be exploited automatically, at scale.
What to do
- Upgrade LY Corporation Armeria to 1.43.0 or later.
- Until it is patched, keep it off the internet or behind a VPN, allowlist or authenticating proxy.
- Warn the people who use it, and filter files and links on the way in.
Description from NVD
A vulnerability has been identified in armeria versions 0.84.0 through 1.42.0, where any-origin CORS policies do not enforce configured path restrictions, allowing an attacker-controlled website visited by an authenticated victim to read sensitive responses from excluded paths when credentials are enabled and the victim's browser sends authentication credentials.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- LY Corporation Armeria. Start from where it runs and what it is connected to.
Trust boundaries in play
- Internet-facing entry points. No account is needed. Any instance reachable from outside your perimeter, through a load balancer, gateway, VPN or exposed admin port, is in scope.
- People who open files and links. Mail, chat and browsers are the delivery path.
Questions to answer about your own systems
- Where does LY Corporation Armeria run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.