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CVE-2026-56000 is a heap use-after-free in GLX context-tag handling in the X.Org X server and Xwayland. CommonMakeCurrent() retains oldTag, a pointer into the per-client contextTags array. During CommonMakeNewCurrent(), allocation of a new context tag can grow that array with realloc(), invalidating oldTag if the allocation moves. A subsequent GlxFreeContextTag(oldTag) writes through the dangling pointer into freed heap memory. The upstream correction frees the old context tag before the operation that may reallocate the contextTags array.
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21 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A vulnerability in the Xorg X server that may permit privilege escalation when the X server runs with privileges.
A heap use-after-free vulnerability in X.Org xorg-server and xwayland involving CommonMakeCurrent(), allowing a local attacker with an X connection and ability to provide a GLX context to trigger memory corruption.
A use-after-free vulnerability in the X.Org X server GLX CommonMakeCurrent logic, where realloc of the contextTags array can invalidate oldTag and subsequent GlxFreeContextTag(oldTag) writes into freed memory.
Use-after-free vulnerability in X.Org Server/Xwayland GLX contextTags handling within CommonMakeCurrent(), caused by stale pointer use after realloc(), potentially leading to memory corruption.
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Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.