# CVE-2026-98626: bpf: Restrict CO-RE poisoning to relocatable instructions

> A local attacker can exploit improper CO-RE relocation handling in the Linux kernel to inject malicious code or escalate privileges.

- **Severity:** Not scored
- **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:** 18 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-108947, BELL-CVE-2026-98626, DEBIAN-CVE-2026-98626, GHSA-7qcx-cmxq-wh7w, UBUNTU-CVE-2026-98626

## What is CVE-2026-98626?

CVE-2026-98626 is a code injection vulnerability in Linux, published on 18 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: Restrict CO-RE poisoning to relocatable instructions

CO-RE relocation records can name any instruction offset. When a
relocation cannot be resolved, bpf_core_patch_insn() currently poisons its
target before checking whether that instruction is a valid relocation
target. Malformed metadata can therefore replace jumps, calls, exits,
register-source arithmetic, or non-immediate loads instead of failing at
the relocation step.

Handle poisoning only after the instruction has passed the same class and
operand-form checks used for a resolved relocation. Route invalid forms
through the existing diagnostic and return a hard error. Keep poisoning
supported instructions, including both halves of a plain ldimm64, so an
unresolved relocation in dead code remains valid.

Extend bpf_core_poison_insn() to poison both halves of ldimm64, and return
its status directly from each validated instruction case. This avoids
routing the success path through a common label and leaves the helper free
to report errors.

The shared relocation code applies this restriction to both libbpf and
in-kernel CO-RE.

## Which versions are affected by CVE-2026-98626?


## How do I fix CVE-2026-98626?

Apply the vendor's patch.

## Is CVE-2026-98626 being exploited?

There is no known exploitation of CVE-2026-98626 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98626 and fix it if it is affected.

What it is: CVE-2026-98626 is a code injection vulnerability in Linux, published on 18 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-2026-98626 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-2026-98626/ (Markdown: https://insights.sbomify.com/CVE-2026-98626/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98626
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98626
- OSV: https://osv.dev/vulnerability/CVE-2026-98626

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98626/
Summaries are generated and may contain mistakes; the official description above is the record.