In the Linux kernel, the following vulnerability has been resolved: tracing/user_events: Clear copied tracing state before fork duplication… (CVE-2026-89750)
A use-after-free (UAF) vulnerability in the Linux kernel's tracing/user_events subsystem was resolved. The flaw occurs because the child process inherits a pointer to user_event_mm from the parent without proper reference counting. If allocation fails during fork duplication, the child process may free memory that the parent still references, leading to a UAF condition detected by KASAN. The fix clears the copied pointer on failure to prevent the child from freeing memory it does not own.
AI Analysis
Technical Summary
The vulnerability in the Linux kernel involves improper handling of the user_event_mm pointer during fork duplication in dup_task_struct(). The child process inherits the parent's user_event_mm pointer without acquiring a reference. If user_event_mm_alloc() fails, user_event_mm_dup() does not clear the copied pointer, leaving the child with a stale pointer. When the child exits, it decrements a reference count on memory it does not own, causing a use-after-free. The kernel's KASAN tool reports this as a slab-use-after-free bug. The patch clears the copied pointer before any failure to prevent the child from freeing memory it should not.
Potential Impact
This vulnerability can cause a use-after-free condition in the kernel, potentially leading to memory corruption or kernel instability. The input data does not describe active exploitation or specific impacts beyond the UAF detection by KASAN. No known exploits in the wild have been reported.
Mitigation Recommendations
A fix has been implemented that clears the copied user_event_mm pointer before any failure during fork duplication, preventing the child process from freeing memory it does not own. Users should apply the official kernel patch that addresses this issue. Since this is a kernel vulnerability, upgrading to a fixed kernel version is the recommended remediation.
In the Linux kernel, the following vulnerability has been resolved: tracing/user_events: Clear copied tracing state before fork duplication… (CVE-2026-89750)
Description
A use-after-free (UAF) vulnerability in the Linux kernel's tracing/user_events subsystem was resolved. The flaw occurs because the child process inherits a pointer to user_event_mm from the parent without proper reference counting. If allocation fails during fork duplication, the child process may free memory that the parent still references, leading to a UAF condition detected by KASAN. The fix clears the copied pointer on failure to prevent the child from freeing memory it does not own.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in the Linux kernel involves improper handling of the user_event_mm pointer during fork duplication in dup_task_struct(). The child process inherits the parent's user_event_mm pointer without acquiring a reference. If user_event_mm_alloc() fails, user_event_mm_dup() does not clear the copied pointer, leaving the child with a stale pointer. When the child exits, it decrements a reference count on memory it does not own, causing a use-after-free. The kernel's KASAN tool reports this as a slab-use-after-free bug. The patch clears the copied pointer before any failure to prevent the child from freeing memory it should not.
Potential Impact
This vulnerability can cause a use-after-free condition in the kernel, potentially leading to memory corruption or kernel instability. The input data does not describe active exploitation or specific impacts beyond the UAF detection by KASAN. No known exploits in the wild have been reported.
Mitigation Recommendations
A fix has been implemented that clears the copied user_event_mm pointer before any failure during fork duplication, preventing the child process from freeing memory it does not own. Users should apply the official kernel patch that addresses this issue. Since this is a kernel vulnerability, upgrading to a fixed kernel version is the recommended remediation.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-pf29-fjpw-v4g4
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-89750"]
Threat ID: 6aa49ff655bf5e2cf5a865ab
Added to database: 09/12/2026, 00:42:30 UTC
Last enriched: 09/12/2026, 00:47:09 UTC
Last updated: 09/12/2026, 00:47:09 UTC
Views: 2
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