CVE-2026-121604— wlroots before 0.20.2 Out-of-Bounds Read via read_surface_class() in xwm.c

Quick assessment

Affected

wlroots wlroots

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 0.20.2 版本之前的 wlroots 中，文件里的函数存在一个越界读取漏洞。该漏洞允许本地 X11 客户端泄露合成器（compositor）的堆内存。攻击者可以设置一个以空字节（NUL）终止实例部分、但类（class）部分未终止的属性，从而通过 IPC 将堆内存中多读取的字节作为窗口类名或应用程序 ID（app_id）暴露出去。

CVSS 3.3 · Low Updated Nov 04, 2026

Possible ATT&CK Techniques 1 AI

T1055 · Process Injection

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Vulnerability Information

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Vulnerability Title

wlroots before 0.20.2 Out-of-Bounds Read via read_surface_class() in xwm.c

Source: CVE Program / CVE List V5

Vulnerability Description

wlroots before 0.20.2 contains an out-of-bounds read vulnerability in read_surface_class() in xwayland/xwm.c that allows local X11 clients to leak compositor heap memory. Attackers can set a WM_CLASS property with a NUL-terminated instance but unterminated class, exposing over-read heap bytes as the window class or app_id over IPC.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Source: CVE Program / CVE List V5

Vulnerability Type

跨界内存读

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
wlroots	wlroots	0 ~ 0.20.2	-

II. Public POCs for CVE-2026-121604

#	POC Description	Source Link	Shenlong Link

AI-Generated POC Premium

No public POC found.

III. Intelligence Information for CVE-2026-121604

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Other References for CVE-2026-121604 (7)

https://gitlab.freedesktop.org/wlroots/wlroots/-/commit/851cdd0089004884bd85a95ad21f04009cb5a53a patch
https://gitlab.freedesktop.org/wlroots/wlroots/-/releases/0.20.2 release-notes
https://gitlab.freedesktop.org/wlroots/wlroots/-/blob/0.20.1/xwayland/xwm.c#L661-L678 technical-description
https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/5374 issue-tracking
https://gitlab.freedesktop.org/wlroots/wlroots/-/work_items/4092 issue-tracking
https://gitlab.freedesktop.org/wlroots/wlroots/-/commit/4412992469540b1d578cb94a5cd4e6e5829812dc patch
https://www.vulncheck.com/advisories/wlroots-before-0.20.2-out-of-bounds-read-via-read-surface-class-in-xwm-c third-party-advisory

https://www.cve.org/CVERecord?id=CVE-2026-121604

IV. Related Vulnerabilities

Same weakness: CWE-125