# CVE-2026-72426: bpf: Preserve pointer spill metadata during half-slot cleanup

> A flaw in the Linux kernel BPF verifier allows pointer spill metadata loss, potentially enabling memory corruption and privilege escalation.

- **Severity:** High 8.4 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-72426, GHSA-v693-v3px-mxpc, UBUNTU-CVE-2026-72426

## What is CVE-2026-72426?

CVE-2026-72426 is a high-severity memory corruption vulnerability in Linux, published on 15 Aug 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 pointer spill metadata during half-slot cleanup

__clean_func_state() cleans dead stack slots in 4-byte halves. When the
high half of a STACK_SPILL slot is dead and the low half remains live,
cleanup converts the live low half to STACK_MISC or STACK_ZERO and clears
the saved spilled_ptr metadata.

That conversion is safe only for scalar spills. For a pointer spill, this
metadata clear lets a later 32-bit fill from the still-live half avoid the
normal non-scalar register-fill check and be treated as an ordinary scalar
stack read.

Leave non-scalar spill slots intact in this half-live shape. This is
conservative for pruning and preserves the existing
check_stack_read_fixed_off() rejection path for partial fills from pointer
spills.

## Which versions are affected by CVE-2026-72426?


## How do I fix CVE-2026-72426?

Apply the vendor's patch.

## Is CVE-2026-72426 being exploited?

There is no known exploitation of CVE-2026-72426 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72426 and fix it if it is affected.

What it is: CVE-2026-72426 is a high-severity memory corruption vulnerability in Linux, published on 15 Aug 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-2026-72426 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-2026-72426/ (Markdown: https://insights.sbomify.com/CVE-2026-72426/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72426
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72426
- OSV: https://osv.dev/vulnerability/CVE-2026-72426

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72426/
Summaries are generated and may contain mistakes; the official description above is the record.