CVE-2026-59691

Summary

A heap buffer overflow vulnerability was found in GStreamer's rfbsrc plugin. When a client connects to a malicious RFB/VNC server that advertises a 16bpp framebuffer and sends Hextile-encoded updates, the Hextile background fill path writes 32-bit pixel values into a buffer allocated for 16-bit pixels. This type mismatch causes an out-of-bounds heap write that can lead to denial of service (process crash) and potential memory corruption.

Affected Software

VendorProductVersion RangeStatus
Red HatRed Hat Enterprise Linux 100:1.26.7-2.el10_2.6 < *unaffected
Red HatRed Hat Enterprise Linux 10.0 Extended Update Support0:1.24.11-3.el10_0.6 < *unaffected
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle Support0:1.10.4-7.el7_9 < *unaffected
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle Support0:0.10.23-26.el7_9 < *unaffected
Red HatRed Hat Enterprise Linux 80:1.16.1-9.el8_10.1 < *unaffected
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support0:1.16.1-4.el8_4.4 < *unaffected
Red HatRed Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On0:1.16.1-4.el8_4.4 < *unaffected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support0:1.16.1-4.el8_6.4 < *unaffected
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On0:1.16.1-4.el8_6.4 < *unaffected
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update Service0:1.16.1-4.el8_8.4 < *unaffected
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP Solutions0:1.16.1-4.el8_8.4 < *unaffected
Red HatRed Hat Enterprise Linux 90:1.22.12-7.el9_8.3 < *unaffected
Red HatRed Hat Enterprise Linux 9.2 Update Services for SAP Solutions0:1.18.4-9.el9_2.5 < *unaffected
Red HatRed Hat Enterprise Linux 9.4 Update Services for SAP Solutions0:1.22.1-6.el9_4.6 < *unaffected
Red HatRed Hat Enterprise Linux 9.6 Extended Update Support0:1.22.12-5.el9_6.6 < *unaffected

Weaknesses

  • CWE-787: Out-of-bounds Write

Workarounds

There is no complete mitigation for this vulnerability. The following measures can reduce risk:

  1. Do not connect GStreamer pipelines using rfbsrc to untrusted or unknown VNC servers.
  2. If the rfbsrc plugin is not required, remove the librfb plugin shared object from the GStreamer plugins directory (typically /usr/lib64/gstreamer-1.0/libgstrfbsrc.so).
  3. Network-level controls (firewall rules) can restrict outbound VNC connections to trusted servers only.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References