CVE-2026-98378 bpf: Skip unsettled links in link iterator
A use-after-free in the Linux kernel BPF link iterator allows local attackers to cause a kernel panic or potentially execute code.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98378?
CVE-2026-98378 is a high-severity use after free vulnerability in Linux, published on 9 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
bpf: Skip unsettled links in link iterator
bpf_link_prime() inserts a link into link_idr before anon_inode_getfile() succeeds and before bpf_link_settle() publishes the ID in link->id. bpf_link_by_id() treats such an ID-zero link as unsettled, but the link iterator takes a reference without this check.
If anon_inode_getfile() then fails, the creator removes the ID and frees its still-private link directly. The iterator is left with a dangling reference and its next bpf_link_put() accesses freed memory.
Treat ID-zero entries as transient in bpf_link_get_curr_or_next(), just as bpf_link_by_id() does.
BUG: KASAN: slab-use-after-free in bpf_link_put Write of size 8 by task exp/384 Call Trace: bpf_link_put kernel/bpf/syscall.c:3372 bpf_link_seq_next kernel/bpf/link_iter.c:33 bpf_seq_read kernel/bpf/bpf_iter.c:158 vfs_read fs/read_write.c:572 ksys_read fs/read_write.c:716 do_syscall_64 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe arch/x86/entry/entry_64.S:121 Kernel panic - not syncing: KASAN: panic_on_warn set ...
Which versions are affected by CVE-2026-98378?
How do I fix CVE-2026-98378?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-98378 being exploited?
There is no known exploitation of CVE-2026-98378 in the wild and no public exploit code.
Sources
Also known as AZL-106905, BELL-CVE-2026-98378, DEBIAN-CVE-2026-98378, GHSA-9m4g-3f3p-3783, UBUNTU-CVE-2026-98378.