# 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.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 9 Oct 2026
- **Updated:** 24 Oct 2026
- **Also known as:** AZL-106905, BELL-CVE-2026-98378, DEBIAN-CVE-2026-98378, GHSA-9m4g-3f3p-3783, UBUNTU-CVE-2026-98378

## 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.

## Is CVE-2026-98378 being exploited?

There is no known exploitation of CVE-2026-98378 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98378 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-98378 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-98378/ (Markdown: https://insights.sbomify.com/CVE-2026-98378/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98378
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98378
- OSV: https://osv.dev/vulnerability/CVE-2026-98378

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98378/
Summaries are generated and may contain mistakes; the official description above is the record.