Quick answers
- Is CVE-2026-109390 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-109390 being exploited in the wild.
- How severe is CVE-2026-109390?
- Critical severity, with a CVSS score of 9.8, published 12 October 2026.
- Which products and versions are affected?
- AnyDesk before 8.0.3.
- Is there a fix for CVE-2026-109390?
- Yes: fixed in 8.0.3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-109390 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-109390?
- Check whether you run AnyDesk 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: 8.0.3
Technical details
The vulnerability exists in AnyDesk's stream packet handler for mode 5 of the session protocol, where a payload length value is not properly validated before being used in a 32-bit allocation calculation. An attacker can declare a payload length of 0xfffffff0, which when incremented by 0x10 wraps to 0 in 32-bit arithmetic, resulting in a minimal allocation while the object retains the original declared length. This allows heap buffer overflow by copying attacker-controlled bytes beyond the allocation boundaries. The exploit leverages heap grooming and ROP gadgets to achieve unauthenticated remote code execution as root on vulnerable Linux systems.
Affected products
- AnyDesk AnyDesk before 8.0.3
Timeline
- 2026-10-12: disclosed
- 2026-10-12: patched: Fixed in version 8.0.3