CVE-2026-53027 Affecting linux-qemu-melange package, versions <6.18.40-r0


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.12% (3rd percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-LINUXQEMUMELANGE-18392583
  • published30 Jul 2026
  • disclosed24 Jun 2026

Introduced: 24 Jun 2026

CVE-2026-53027  (opens in a new tab)

How to fix?

Upgrade Chainguard linux-qemu-melange to version 6.18.40-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-qemu-melange package and not the linux-qemu-melange package as distributed by Chainguard. See How to fix? for Chainguard relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: fix missing run load for vcn0 in attr_data_get_block_locked()

When a compressed or sparse attribute has its clusters frame-aligned, vcn is rounded down to the frame start using cmask, which can result in vcn != vcn0. In this case, vcn and vcn0 may reside in different attribute segments.

The code already handles the case where vcn is in a different segment by loading its runs before allocation. However, it fails to load runs for vcn0 when vcn0 resides in a different segment than vcn. This causes run_lookup_entry() to return SPARSE_LCN for vcn0 since its segment was never loaded into the in-memory run list, triggering the WARN_ON(1).

Fix this by adding a missing check for vcn0 after the existing vcn segment check. If vcn0 falls outside the current segment range [svcn, evcn1), find and load the attribute segment containing vcn0 before performing the run lookup.

The following scenario triggers the bug: attr_data_get_block_locked() vcn = vcn0 & cmask <- vcn != vcn0 after frame alignment load runs for vcn segment <- vcn0 segment not loaded! attr_allocate_clusters() <- allocation succeeds run_lookup_entry(vcn0) <- vcn0 not in run -> SPARSE_LCN WARN_ON(1) <- bug fires here!

CVSS Base Scores

version 3.1