# CVE-2026-99087: Linux kernel dm-integrity NULL pointer dereference with 'R' flag

Source: https://junglewise.ai/threats/cve-2026-99087-in-the-linux-kernel-the-following-vulnerability-has-been-resolved  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-23. Updated: 2026-10-23  
License: CC BY 4.0 with a link back

CVE-2026-99087 · Severity: info · Published 2026-10-23

The Linux kernel's dm-integrity module, which provides data integrity checking for storage devices, crashes with a NULL pointer dereference when a device with a dirty bitmap flag is activated in read-only ('R') mode. This causes the kernel to crash during device resume, leading to denial of service on systems using dm-integrity for protected storage.

Technologies: [Linux Kernel](https://junglewise.ai/threats/technologies/kernel). Vendors: [Linux](https://junglewise.ai/threats/vendors/linux).

## Quick answers

**Is CVE-2026-99087 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-99087 being exploited in the wild.

**How severe is CVE-2026-99087?** Informational severity, published 23 October 2026.

**Which products and versions are affected?** Linux Kernel all versions with dm-integrity bitmap mode support.

**Is there a fix for CVE-2026-99087?** A patch was published on 2026-10-21. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-99087 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-99087?** Check whether you run Linux Kernel at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

dm-integrity crashes in dm_integrity_resume() when attempting to write to a device that has been activated in read-only mode while the SB_FLAG_DIRTY_BITMAP flag is set. The vulnerability is triggered locally by mounting or resuming a dm-integrity device with conflicting flags, causing unprotected write operations on a read-only device. The fix adds a check to skip write operations when the device is in read-only mode.

## Affected products

- Linux Linux kernel all versions with dm-integrity bitmap mode support

## Timeline

- 2026-10-23: disclosed
- 2026-10-21: patched

## References

- [https://git.kernel.org/stable/c/2e25842f0e4423e0efb243f56153d842ed6b933f](https://git.kernel.org/stable/c/2e25842f0e4423e0efb243f56153d842ed6b933f)
- [https://git.kernel.org/stable/c/69ed43ed8a174465fca1ba6bfbde53e4618c8956](https://git.kernel.org/stable/c/69ed43ed8a174465fca1ba6bfbde53e4618c8956)

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