CVE-2026-98642
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix UAF due to concurrent consumption of ttrace lists in alloc_bulk Syzkaller repeatedly triggered UAF splats related to n…
Overview
CVE-2026-98642 is a known-severity vulnerability. It was published on October 18, 2026.
Technical description
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix UAF due to concurrent consumption of ttrace lists in alloc_bulk
Syzkaller repeatedly triggered UAF splats related to nodes in
waiting_for_gp_ttrace within the bpf memalloc:
BUG: KASAN: slab-use-after-free in llist_del_first+0x85/0x110 lib/llist.c:61
Read of size 8 at addr ffff8881572cd080 by task syz.4.470/5112
...
llist_del_first+0x85/0x110 lib/llist.c:61
alloc_bulk+0x193/0x460 kernel/bpf/memalloc.c:229
bpf_mem_refill+0x386/0x560 kernel/bpf/memalloc.c:436
Freed by task 14:
...
__free_rcu kernel/bpf/memalloc.c:281 [inline]
__free_rcu_tasks_trace+0x48/0xd0 kernel/bpf/memalloc.c:291
rcu_tasks_invoke_cbs+0x1ec/0x3e0 kernel/rcu/tasks.h:571
rcu_tasks_one_gp+0x13d/0x220 kernel/rcu/tasks.h:621
rcu_tasks_kthread+0xf3/0x120 kernel/rcu/tasks.h:651
The reason is that the UAF occurs after the RCU Tasks Trace GP expires:
when the __free_rcu() callback runs, there is no synchronization
protecting llist_del_al
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
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Frequently asked questions
What is CVE-2026-98642?
CVE-2026-98642 is a known-severity vulnerability. It was published on October 18, 2026.
How severe is CVE-2026-98642?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-98642?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-98642?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-98642 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.