X.Org libX11 XkbGetMap overflow allows remote code execution
Original title: ZDI-26-906: X.Org Server libX11 XkbGetMap Reply Heap-based Buffer Overflow Remote Code Execution Vulnerability
A victim must connect to a malicious X11 server; ZDI rates CVE-2026-88806 at CVSS 8.8.
ZDI published ZDI-26-906, a heap-based buffer overflow in the libX11 XkbGetMap reply handling of X.Org Server. Remote attackers can execute arbitrary code only if the target connects to a malicious X11 server. ZDI assigned CVE-2026-88806 and a CVSS score of 8.8. No fixed version or exploitation status is stated.
- Tracked as ZDI-26-906 and CVE-2026-88806.
- User interaction is required to connect to a malicious X11 server.
- ZDI assigned a CVSS rating of 8.8.
- Affected and fixed versions are not stated.
Impact: Remote arbitrary code execution after connecting to a malicious X11 server
| Product | Affected |
|---|---|
| X.Org Server libX11 | — |
- 1.Do not connect X clients to untrusted X11 servers.
- CVEs
- CVE-2026-88806
- Vendors
- X.Org
- Products
- X.Org ServerlibX11
Vulnerabilities mentioned
All| CVE | Vulnerability | CVSS | EPSS | Signals | Published |
|---|---|---|---|---|---|
| CVE-2026-88806 | Buffer Overflow in libX11 XkbGetMap Leading to Potential Code Execution | 7.5 | — |
From the original article
This vulnerability allows remote attackers to execute arbitrary code on affected installations of X. Org Server. User interaction is required to exploit this vulnerability in that the target must connect to a malicious X11 server.
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