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CVE-2026-59691 Red Hat CVE debrief

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. The affected product is GStreamer's rfbsrc plugin, and users should be aware of this vulnerability when connecting to untrusted or malicious RFB/VNC servers.

Vendor
Red Hat
Product
Red Hat Enterprise Linux 10
CVSS
HIGH 7.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-09
Original CVE updated
2026-07-28
Advisory published
2026-07-09
Advisory updated
2026-07-28

Who should care

Users of GStreamer's rfbsrc plugin, particularly those who connect to untrusted or malicious RFB/VNC servers, should be aware of this vulnerability and take steps to mitigate it. This includes updating the plugin to the latest version, restricting access to untrusted servers, and monitoring for suspicious activity. Operators, platform administrators, vulnerability management teams, and security teams should review the affected scope and implement compensating controls.

Technical summary

The vulnerability occurs in the Hextile background fill path of the rfbsrc plugin, where 32-bit pixel values are written to a buffer allocated for 16-bit pixels, leading to an out-of-bounds heap write. This can cause denial of service (process crash) and potential memory corruption. The affected product is GStreamer's rfbsrc plugin, and users should be aware of this vulnerability when connecting to untrusted or malicious RFB/VNC servers.

Defensive priority

High

Recommended defensive actions

  • Update GStreamer's rfbsrc plugin to the latest version
  • Restrict access to untrusted or malicious RFB/VNC servers
  • Monitor for suspicious activity and implement compensating controls
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-09T11:16:41.657Z and last modified on 2026-07-28T21:17:28.737Z. The NVD entry is currently Awaiting Analysis. This vulnerability affects GStreamer's rfbsrc plugin, which is used for handling RFB/VNC connections. The plugin's Hextile background fill path is vulnerable to a heap buffer overflow, allowing for potential denial of service and memory corruption. Evidence is limited, and defenders should verify the affected scope and vendor guidance.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-09T11:16:41.657Z and has not been modified since then. The NVD entry is currently Awaiting Analysis.