# CVE-2026-93522: X.Org X Server heap buffer overflow in CopyArea CPU-to-FBO

Source: https://junglewise.ai/threats/cve-2026-93522-a-heap-buffer-overflow-caused-by-mismatched-size-usage-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-28. Updated: 2026-10-28  
License: CC BY 4.0 with a link back

CVE-2026-93522 · Severity: high · CVSS 7.8 · Published 2026-10-28

X.Org X Server is the display server that manages graphical rendering for most Linux systems. A heap buffer overflow in the CopyArea operation allows authenticated users on the same display to crash the X server or potentially execute code with its privileges, compromising the entire graphical environment and potentially enabling system compromise.

Technologies: [X.Org X Server](https://junglewise.ai/threats/technologies/x-org-x-server), [X.Org XWayland](https://junglewise.ai/threats/technologies/x-org-xwayland). Vendors: [X.Org](https://junglewise.ai/threats/vendors/x-org).

## Quick answers

**Is CVE-2026-93522 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-93522 being exploited in the wild.

**How severe is CVE-2026-93522?** High severity, with a CVSS score of 7.8, published 28 October 2026.

**Which products and versions are affected?** X.Org X Server before 21.1.15; X.Org XWayland before 24.1.14.

**Is there a fix for CVE-2026-93522?** Yes: fixed in X Server 21.1.15, XWayland 24.1.14. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-93522 attacked?** It is attacked with local access.

**Am I affected by CVE-2026-93522?** Check whether you run X.Org X Server or X.Org XWayland at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in X Server 21.1.15, XWayland 24.1.14

## Technical details

A heap buffer overflow exists in the glamor_upload_boxes() function due to mismatched size calculations: the tmp_bits buffer is allocated based on destination pixmap height but indexed using source coordinates, causing out-of-bounds writes when the source is taller than the destination. An authenticated X client can trigger this via the CopyArea path by supplying crafted parameters to cause a heap overflow. The fix adjusts buffer sizing to account for source coordinate mapping relative to the destination.

## Affected products

- X.Org X Server before 21.1.15
- X.Org XWayland before 24.1.14

## Timeline

- 2026-10-28: disclosed: CVE-2026-93522 published

## References

- [https://gitlab.freedesktop.org/xorg/xserver/-/commit/ad26c26bf795e6464f74c8ef5bb1d41403d877ab](https://gitlab.freedesktop.org/xorg/xserver/-/commit/ad26c26bf795e6464f74c8ef5bb1d41403d877ab)

## Related threats

- [X.Org X Server use after free in gesture sprite lifecycle](https://junglewise.ai/threats/cve-2026-93536-a-use-after-free-caused-by-missing-lifecycle-management-of)
- [X.Org X Server buffer overread in CheckKeySyms](https://junglewise.ai/threats/cve-2026-93524-a-buffer-overread-in-checkkeysyms-in-x-org-x-server-before-21-1)
- [X.Org X Server heap buffer overflow in XIPassiveUngrabDevice](https://junglewise.ai/threats/cve-2026-93523-a-heap-buffer-overflow-caused-by-a-xipassiveungrabdevice-request)
- [X.Org X Server buffer overflow in RandR ChangeProviderProperty](https://junglewise.ai/threats/cve-2026-93521-a-buffer-overflow-in-randr-changeproviderproperty-requests-in-x)
- [X.org X server heap buffer overflow in XkbAllocNames](https://junglewise.ai/threats/cve-2026-93520-a-heap-buffer-overflow-caused-by-mismatching-size-calculations)