PatchSiren cyber security CVE debrief

CVE-2026-46005 Linux CVE debrief

A resource leak vulnerability in the Linux kernel's XFS filesystem could allow reference count imbalance on DAX-capable block devices. The flaw exists in xfs_alloc_buftarg() where error paths fail to release a held DAX device reference via fs_put_dax(). Successful exploitation could lead to resource exhaustion or use-after-free conditions in DAX-enabled XFS deployments. The vulnerability was resolved by adding the missing fs_put_dax() call in error handling paths.

Vendor: Linux
Product: Unknown
CVSS: MEDIUM 5.5
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-05-27
Original CVE updated: 2026-06-19
Advisory published: 2026-05-27
Advisory updated: 2026-06-19

Who should care

Linux system administrators running XFS with DAX-enabled storage, kernel maintainers, and organizations using persistent memory or DAX-capable block devices with XFS filesystems.

Technical summary

The xfs_alloc_buftarg() function in the Linux kernel's XFS filesystem driver failed to release a DAX device reference on error paths, causing a resource leak. The fix adds fs_put_dax() to properly drop the reference when buffer target allocation fails. This affects systems using DAX (Direct Access) with XFS filesystems.

Defensive priority

medium

Recommended defensive actions

Apply kernel updates containing the xfs_alloc_buftarg() fix when available from your Linux distribution
Monitor for stable kernel backports referencing commits 28a6c132b8c6, 29a7b2614357, 5804cb507233, 5c293a1e1ef0, or 82fb9da6477d
Review systems using DAX-enabled XFS filesystems for potential resource exhaustion indicators
Validate XFS mount operations complete successfully without error path triggering
Consider disabling DAX on XFS filesystems where not strictly required until patched
Audit kernel logs for xfs_alloc_buftarg failure patterns that might indicate exploitation attempts

Evidence notes

The CVE description confirms this is a resource leak fix in xfs_alloc_buftarg() where fs_put_dax() was missing from error paths. Multiple stable kernel commits are referenced, indicating backports across kernel versions. The fix adds proper DAX device reference cleanup when buffer target allocation fails.

Sources and references

Verified primary and authoritative sources

CVE-2026-46005 CVE Program record
Publisher, destination, and source semantics verified

URL: https://www.cve.org/CVERecord?id=CVE-2026-46005

CVE Program - Official CVE Program record with source-provided CVE metadata.
CVE-2026-46005 NVD vulnerability detail
Publisher, destination, and source semantics verified

URL: https://nvd.nist.gov/vuln/detail/CVE-2026-46005

NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Source reference
Unverified legacy reference

URL: https://git.kernel.org/stable/c/28a6c132b8c6e5eeefa889c4fb43d65b12989d48

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Source reference
Unverified legacy reference

URL: https://git.kernel.org/stable/c/29a7b2614357393b176ef06ba5bc3ff5afc8df69

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Source reference
Unverified legacy reference

URL: https://git.kernel.org/stable/c/5804cb507233ed767a83ac70527b2f6c4566ec75

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Source reference
Unverified legacy reference

URL: https://git.kernel.org/stable/c/5c293a1e1ef0f838772d20ae8afae4cbd87cd3f9

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Source reference
Unverified legacy reference

URL: https://git.kernel.org/stable/c/82fb9da6477d08bdab954dc7bc081a41f2f9cae6

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.