CVE-2026-123976Teunis van Beelen EDFbrowser out-of-bounds write
CVE-2026-123976 is a out-of-bounds write in Teunis van Beelen EDFbrowser, rated medium (6.8 on CVSS 4.0).
Why this priority: Medium severity, with no exploitation signal.
Published · Updated · NVD status: Received
What it is
Code writes past the end of a buffer, corrupting memory in ways an attacker can often turn into code execution.
How it is reached
An attacker can exploit it by someone who can already run code or sign in on the machine, without an account, but someone has to act first, such as opening a file or following a link.
What an attacker gains
A successful attack can take it offline. In practice, this kind of flaw lets an attacker crash the process, read memory, or in the worst case run code.
Is it being exploited?
There is no public report of exploitation yet.
What to do
- Upgrade Teunis van Beelen EDFbrowser to 2.16 or later.
- Limit who can run code or sign in on the hosts that run it.
- Warn the people who use it, and filter files and links on the way in.
Description from NVD
EDFbrowser before 2.16 contains an out-of-bounds write vulnerability in check_edf_file() that allows attackers to overflow the 256-element annot_ch array by supplying excessive annotation signals. Attackers can craft an EDF+ or BDF+ file with more than 256 annotation signals to overwrite edfhdrblock members, including the signal parameter pointer, crashing the application when opened.
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
- Native code: operating systems, browsers and firmware. The flaw sits wherever native code reads untrusted data.
- Network appliances and media or file parsers. The flaw sits wherever native code reads untrusted data.
Trust boundaries in play
- Host boundary. The attacker needs a foothold on the machine first; the flaw turns a small foothold into a bigger one.
- People who open files and links. Mail, chat and browsers are the delivery path.
- Wherever native code reads untrusted data. An attacker who crosses it can crash the process, read memory, or in the worst case run code.
Questions to answer about your own systems
- Where does Teunis van Beelen EDFbrowser run in your systems, and at which version?
- Which of those hosts also run code or users you do not fully trust?
- What can it reach once compromised: which data stores, secrets and services?
Read more
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.