Stack-based buffer overflow in X.Org X server and Xwayland font alias resolution
CVE-2026-50256 is a stack-based buffer overflow in the X.Org X server and Xwayland during font alias resolution. The flaw is caused by a length mismatch between the X server and libXfont2: the server allocates a 256-byte stack buffer for an alias target name, while libXfont2 permits alias target names up to 1024 bytes. When processing a font alias target name between 257 and 1023 bytes, the X server copies the name into the undersized stack buffer without sufficient bounds checking, resulting in a stack overflow. According to the provided advisory context, this affects X.Org X server versions prior to 21.1.23 and Xwayland versions prior to 24.1.12.
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Impact
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Exploits
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Affected products & vendors
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Recent activity
6 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.