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CVE-2026-52720 Red Hat CVE debrief

A heap buffer overflow vulnerability was found in GStreamer's librfb (RFB/VNC client). The rectangle bounds check incorrectly validates area rather than individual dimensions, allowing a malicious VNC server to send a rectangle that extends beyond the framebuffer. A remote attacker could set up a malicious VNC server and trick a user into connecting, resulting in an out-of-bounds heap write that could lead to code execution or a crash.

Vendor
Red Hat
Product
Red Hat Enterprise Linux 10
CVSS
HIGH 8.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-15
Original CVE updated
2026-08-03
Advisory published
2026-06-15
Advisory updated
2026-08-03

Who should care

Users of GStreamer's librfb (RFB/VNC client) should be aware of this vulnerability and take steps to mitigate it.

Technical summary

The vulnerability is caused by the rectangle bounds check incorrectly validating area rather than individual dimensions. This allows a malicious VNC server to send a rectangle that extends beyond the framebuffer, resulting in an out-of-bounds heap write.

Defensive priority

HIGH

Recommended defensive actions

  • Apply patches or updates from the vendor as soon as they are available.
  • Use secure VNC connections and validate the authenticity of VNC servers.
  • Limit access to VNC servers to trusted users and networks.

Evidence notes

The CVE-2026-52720 vulnerability has been reported by Redhat. For more information, see resourceLinkAnnotations: [ref-4, ref-5, ref-6].

Sources and references

Verified primary and authoritative sources

  • CVE-2026-52720 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-52720

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-52720 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-52720

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.