CVE-2026-89576
Received Received - Intake

dm-era Metadata Block Leak on Take-Snap Failure

Publication date: 2026-09-11

Last updated on: 2026-09-11

Assigner: kernel.org

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().

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Meta Information

Published
2026-09-11
Last Modified
2026-09-11
Generated
2026-09-12
AI Q&A
2026-09-11
EPSS Evaluated
N/A
NVD
CVE-2026-89576
EUVD
EUVD-2026-76488

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a memory leak in the device-mapper era (dm-era) target. When taking a metadata snapshot fails after allocating a new block, the function does not properly release the shadow block. This causes a permanent leak of one metadata block per failed snapshot attempt.

Detection Guidance

This vulnerability is specific to the Linux kernel's device-mapper era target (dm-era). Detection requires checking kernel logs for errors related to dm-era operations or metadata snapshot failures. Use commands like dmesg | grep dm-era or journalctl -k | grep dm-era to search for relevant errors.

Impact Analysis

The impact is primarily on systems using the dm-era feature. Each failed snapshot attempt leaks a metadata block, which could eventually exhaust metadata space. This may lead to system instability or failure if metadata space is depleted.

Mitigation Strategies

Apply the latest Linux kernel update that includes the fix for this vulnerability. Monitor kernel logs for dm-era errors and ensure no metadata block leaks are occurring. If using dm-era, verify snapshot operations complete successfully to avoid leaks.

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