Researchers Publish Working Exploit for Pre-Auth AnyDesk Linux Flaw That Gives Root Access

Overview of the AnyDesk Linux Vulnerability

Security researchers have published a working exploit for a pre-authentication remote code execution flaw in AnyDesk Linux, which allows attackers to gain root access before a connection is approved. The vulnerability was patched in version 8.0.3, but the company's changelog did not explicitly reference the flaw. The exploit, named AnyPwn, targets a heap buffer overflow in AnyDesk's session protocol, a remote desktop tool. The code was released on GitHub on October 8, 2026.

Exploit Mechanics and Scope

The exploit works only over direct TCP connections on port 7070. It is probabilistic, requiring the heap layout to place a target object adjacent to the overflowed buffer. If this condition is not met, the service crashes instead of executing the attacker's command. The offsets in the published code target a specific build of AnyDesk Linux, version 8.0.2; other builds would require different values.

The researchers suggest that the same vulnerable code path is also reachable via AnyDesk's relay servers, which the software uses when a direct connection is unavailable. However, they validated this with a Frida instrumentation trigger but did not demonstrate the full exploit chain over relays. AnyDesk stated in June that the vulnerability is limited to direct connections on Linux and does not affect Windows or macOS.

Vendor Response and Patching

AnyDesk acknowledged the vulnerability on June 23, 2026, and released version 8.0.3 with the fix. However, the company's changelog described the fix only as 'fixed a bug that could lead to a crash,' with no CVE assigned and no formal security advisory. As of October 9, 2026, no CVE has been assigned to the vulnerability, and AnyDesk has not issued a formal security advisory.

The AnyDesk download page no longer lists version 8.0.2, though it still appears in the changelog. The researchers noted that the vendor may have deleted the 8.0.2 build of AnyDesk upon the release of their proof-of-concept video.

Technical Details of the Flaw

AnyDesk's session protocol uses mode-5 stream packets. The handler calculates the size of its backing allocation by adding a 16-byte header to the declared payload length, using 32-bit arithmetic without overflow checking. The exploit declares a payload length of 0xFFFFFFF0, which causes the 32-bit result to wrap to zero. This results in the allocator reserving a tiny buffer while the object records the original large length. Even one byte of attacker data then writes past the end of the allocation, corrupting fields in adjacent heap objects. The exploit uses a ROP chain to run an arbitrary command as root.

Broader Context and Implications

The vulnerability was discovered by Rick de Jager of the V12 security team using V12, a security code review engine. V12's founders previously built security firm Zellic and led the competitive hacking team Perfect Blue. A separate AnyDesk heap buffer overflow, CVE-2025-27918, was fixed in version 7.0.0 in April 2025. That vulnerability affected all AnyDesk platforms and involved an integer overflow in user image processing, a different mechanism from AnyPwn's session protocol flaw.

AnyDesk was hacked in early 2024 in a separate incident in which the company's production systems were breached, leading to certificate revocations and forced password resets. This incident highlights the ongoing challenges AnyDesk faces in securing its infrastructure and responding to vulnerabilities.

Recommendations for Administrators

Administrators should update AnyDesk Linux to at least version 8.0.3. The latest release is 8.1.0. If immediate updates are not possible, administrators can reduce exposure by restricting access to TCP port 7070. Whether the flaw is fully exploitable over relay connections remains unresolved, and further research is needed to confirm this.

Source: The Hacker News. Analysis based on publicly available information; no hands-on testing is claimed.