# CVE-2026-98628: bpf: Make post-verification instruction rewrites killable

> A privileged user can cause a denial of service by submitting BPF programs that trigger long-running, non-killable post-verification instruction rewrites.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **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-109422, BELL-CVE-2026-98628, DEBIAN-CVE-2026-98628, GHSA-mq6p-2mw2-mp6g, UBUNTU-CVE-2026-98628

## What is CVE-2026-98628?

CVE-2026-98628 is a denial of service 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: Make post-verification instruction rewrites killable

After do_check() returns, the verifier runs several instruction rewrite
passes. Some of them patch or remove one instruction at a time. Each
operation moves the remaining instruction and auxiliary-data arrays and
adjusts all branch offsets, making the overall work quadratic in the
program length.

A privileged loader can submit 131072 unconditional jumps by zero followed
by a valid return. Verification finishes quickly, but bpf_opt_remove_nops()
then spends a long time removing each jump separately. Since this
post-verification work neither checks for signals nor reschedules, a pending
SIGKILL cannot terminate the task until the rewrite finishes.

Make bpf_patch_insn_data() and verifier_remove_insns() common cancellation
and rescheduling points. These helpers run from BPF_PROG_LOAD process
context, and bpf_patch_insn_data() can already sleep while reallocating
auxiliary data.

Report interrupted constant blinding as -EINTR and propagate it through
both JIT paths, including kernels that permit interpreter fallback.
Other blinding failures retain the existing fallback behavior.

This does not reduce the quadratic cost of the rewrite passes, but it makes
the work preemptible and allows a killed loader to be torn down promptly.

## Which versions are affected by CVE-2026-98628?


## How do I fix CVE-2026-98628?

Apply the vendor's patch.

## Is CVE-2026-98628 being exploited?

There is no known exploitation of CVE-2026-98628 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98628 and fix it if it is affected.

What it is: CVE-2026-98628 is a denial of service 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-2026-98628 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-2026-98628/ (Markdown: https://insights.sbomify.com/CVE-2026-98628/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98628
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98628
- OSV: https://osv.dev/vulnerability/CVE-2026-98628

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98628/
Summaries are generated and may contain mistakes; the official description above is the record.