CVE-2026-121964FreeRDP heap-based buffer overflow
CVE-2026-121964 is a heap-based buffer overflow in FreeRDP, rated high (8.7 on CVSS 4.0).
Why this priority: A public proof of concept exists and exploitation can be automated.
Published · Updated · NVD status: Modified
What it is
A buffer on the heap overflows and corrupts neighbouring data structures.
How it is reached
An attacker can exploit it over the network, without an account, and nobody has to click anything.
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?
CISA's SSVC assessment notes a public proof of concept. It can be exploited automatically, at scale. EPSS estimates a 0.57% chance of exploitation activity in the next 30 days, higher than 48% of scored CVEs.
What to do
- Upgrade FreeRDP to 3.32.2 or later.
- Until it is patched, keep it off the internet or behind a VPN, allowlist or authenticating proxy.
Description from NVD
FreeRDP before 3.32.2 contains a heap-based buffer overflow in the RD Gateway RPC client, where rpc_client_recv_fragment writes BIND_ACK and ALTER_CONTEXT_RESP fragments into a persistent PDU stream after checking only total capacity rather than remaining capacity from the current stream position. A malicious or compromised RD Gateway can send crafted RPC fragments with manipulated alloc_hint and frag_length values to overwrite client heap memory with attacker-controlled data, causing a crash or potentially arbitrary code execution.
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
- 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.
- 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 FreeRDP 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?
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.