# CVE-2026-98627: bpf: Preserve packet pointer class displacement in regsafe()

> A flaw in the Linux kernel BPF verifier allows out-of-bounds packet access, potentially leading to memory corruption and privilege escalation for local attackers.

- **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:** DEBIAN-CVE-2026-98627, GHSA-p3gw-45vq-6cwq, UBUNTU-CVE-2026-98627

## What is CVE-2026-98627?

CVE-2026-98627 is a memory corruption 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: Preserve packet pointer class displacement in regsafe()

regsafe() maps packet pointer IDs between states and checks that each
current register range is a subset of the corresponding explored
register range. It does not, however, preserve the displacement between
registers that share a packet pointer ID.

This is unsound because packet range is shared by ID. A bounds check on
one class member updates every member, and a later access can consume the
range through another member. Commit 022ac0750883 ("bpf: use reg->var_off
instead of reg->off for pointers") folded the fixed pointer offset into
r64 and removed the old off equality check, so two individually narrower
registers can prune even when their displacement has changed. The
explored path can then license an out-of-bounds packet access on the
pruned path.

Require matching range bases for packet pointers with an ID. Together
with the existing ID mapping, this preserves the displacement between
members of each packet-pointer class without adding per-ID state.
Packet pointers without an ID remain unaffected.

## Which versions are affected by CVE-2026-98627?


## How do I fix CVE-2026-98627?

Apply the vendor's patch.

## Is CVE-2026-98627 being exploited?

There is no known exploitation of CVE-2026-98627 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98627 and fix it if it is affected.

What it is: CVE-2026-98627 is a memory corruption 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-2026-98627 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-2026-98627/ (Markdown: https://insights.sbomify.com/CVE-2026-98627/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98627
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98627
- OSV: https://osv.dev/vulnerability/CVE-2026-98627

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98627/
Summaries are generated and may contain mistakes; the official description above is the record.