Junglewise Threat Intelligence

CVE-2026-5405: Wireshark heap overflow in RDP dissector

CVE-2026-5405 · Severity: high · CVSS 7.8 · Published 2026-05-01

Vendors: Wireshark Foundation.

Executive brief

Wireshark, a widely used network protocol analyzer, is vulnerable to a flaw in its Remote Desktop Protocol (RDP) analysis component. An attacker can exploit this by sending a specially crafted network packet or tricking a user into opening a malicious capture file. This could result in the application crashing or potentially allow the attacker to execute unauthorized code on the system.

Technical details

A heap-based buffer overflow exists in the RDP dissector's ZGFX decompression logic, specifically within the rdp8_decompress_segment() function in epan/tvbuff_rdp.c. The vulnerability is caused by a lack of bounds checking on the uncompressed path when copying attacker-controlled data into a fixed 65,536-byte outputSegment buffer. An attacker can trigger this overflow by providing a ZGFX segment larger than the buffer size. This is reachable through the standard RDP dissection chain (TCP 3389) via the Microsoft::Windows::RDS::Graphics dynamic channel. Successful exploitation can lead to a crash (SIGSEGV) or arbitrary code execution. Patches are available in Wireshark versions 4.6.5 and 4.4.15.

Affected products

  • Wireshark Foundation Wireshark 4.6.0 to 4.6.4, 4.4.0 to 4.4.14

Timeline

  • 2026-04-29: advisory: Wireshark published wnpa-sec-2026-17
  • 2026-05-01: disclosed: NVD publication date
  • 2026-05-26: patched: Red Hat released security updates for RHEL 10

References