CVE-2026-121819LY Corporation Armeria link following
CVE-2026-121819 is a link following in LY Corporation Armeria, rated medium (5.9 on CVSS 4.0).
Why this priority: Medium severity, with no exploitation signal.
Published · Updated · NVD status: Deferred
What it is
The software follows a symbolic link an attacker planted, so it reads or writes a file other than the one it checked.
How it is reached
An attacker can exploit it over the network, with an administrator account, and nobody has to click anything. Success also depends on conditions the attacker does not fully control.
What an attacker gains
A successful attack can read the data it protects. In practice, this kind of flaw lets an attacker read or write files outside the folders the service meant to expose.
Is it being exploited?
There is no public report of exploitation yet.
What to do
- Upgrade LY Corporation Armeria to 1.43.0 or later.
- Until it is patched, review who holds accounts that can reach it.
Description from NVD
A vulnerability has been identified in armeria-xds versions 1.40.0 through 1.42.0, where DataSourcePolicy checks filename containment without resolving symbolic links, allowing a compromised or semi-trusted xDS control plane to cause the xDS client to read files outside configured allowed root directories when a symbolic link inside an allowed directory points outside it. In deployments using a credential injector, header-compatible text secrets may be exposed to an attacker-observable upstream.
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
- File storage the service can read or write. The flaw sits between the application and the file system it can reach.
Trust boundaries in play
- Authenticated network access. An account is needed, so exposure follows who can sign in: customers, partners or staff.
- Between the application and the file system it can reach. An attacker who crosses it can read or write files outside the folders the service meant to expose.
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.