15-year-old GhostLock Kernel Flaw Enables Privilege Escalation in Major Linux Distributions
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A critical Linux kernel vulnerability, tracked as CVE-2026-43499 and dubbed \u201cGhostLock<\/a>,\u201d has been disclosed by security researchers at VEGA, exposing a privilege escalation flaw that has silently affected major Linux distributions for over a decade.<\/p>\n GhostLock originates from a logic error in the kernel\u2019s real-time mutex (rtmutex) subsystem, introduced in Linux version 2.6.39 in 2011. The flaw remained undiscovered until it was patched in April 2026, impacting all kernels up to version 7.1.<\/p>\n Nebula Security researchers demonstrated a highly reliable exploit with a 97% success rate, earning a $92,337 reward through Google\u2019s kernelCTF program.<\/p>\n At its core, the vulnerability allows an unprivileged local attacker to manipulate kernel memory and ultimately gain root privileges<\/a>.<\/p>\n The issue arises in the remove_waiter() function, which incorrectly clears a pointer associated with the currently executing task instead of the actual waiting task during certain futex operations.<\/p>\n This bug causes a dangling pointer to reference freed kernel stack memory. The flaw is exploitable via a specific race condition involving priority-inheritance futexes.<\/p>\n