CVE-2026-98378bpf: Skip unsettled links in link iterator

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 ...

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/68930f8d40ab4c10ca3b019f076136758fd100a8
• https://git.kernel.org/stable/c/c251ed48bd9063cf7de6049421e78b6de989060f
• https://git.kernel.org/stable/c/798a61edbc436cacdb659927d067368eeb1e30e2
• https://git.kernel.org/stable/c/6e271f093d15d323f42de26f66556af53fa8e19f
• https://git.kernel.org/stable/c/87ce4b53b7436b50fc984f0a6afaf77f68ac5573
• https://git.kernel.org/stable/c/50e80e2bb5e2be8515205b9c496b9640ddefa434