CVE-2026-93111 bpf: Mark tracing_multi trampolines as ftrace managed
A missing flag in Linux kernel BPF tracing causes a kernel warning and potential instability when releasing links, requiring a patch to fix.
- 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-2026-93111?
CVE-2026-93111 is a high-severity denial of service vulnerability in Linux, published on 17 Sep 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: Mark tracing_multi trampolines as ftrace managed
Since tracing_multi link does not set ftrace_managed, it would fail to release the tracing_multi link when attaching tracing_multi link and then attaching fentry link.
[ 3.714215] WARNING: kernel/bpf/trampoline.c:1727 at bpf_trampoline_multi_detach+0x20b/0x240, CPU#1: test_progs/97 ... [ 3.733170] bpf_tracing_multi_link_release+0x14/0x30 [ 3.733890] bpf_link_free+0x58/0x130 [ 3.734414] bpf_link_release+0x23/0x30
Fix it by setting 'ftrace_managed = true' in register_fentry_multi().
Which versions are affected by CVE-2026-93111?
How do I fix CVE-2026-93111?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-93111 being exploited?
There is no known exploitation of CVE-2026-93111 in the wild and no public exploit code.
Sources
Also known as GHSA-285f-2chv-p9fq, UBUNTU-CVE-2026-93111.