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CVE-2026-46023 Linux CVE debrief

An integer overflow vulnerability in the Linux kernel's device mapper (dm) mirror subsystem could allow an attacker with privileges to configure device mapper tables to trigger out-of-bounds memory reads. The flaw exists in create_dirty_log() where param_count is added to 2 before validation against argc; when param_count is near UINT_MAX, the unsigned addition wraps to a small value, bypassing bounds checks and passing the overflowed value to dm_dirty_log_create(). The fix validates param_count against argc - 2 before performing the addition, matching the pattern used by parse_features() in the same file.

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

Who should care

Linux system administrators using device mapper mirroring (dm-mirror); security teams monitoring kernel memory safety vulnerabilities; organizations with strict privilege separation requirements for storage subsystem configuration

Technical summary

The create_dirty_log() function in drivers/md/dm-mirror.c calculates *args_used = 2 + param_count before validating param_count against argc. With param_count near UINT_MAX, unsigned integer wraparound produces a small *args_used value, causing the argc < *args_used check to pass incorrectly. The overflowed param_count propagates to dm_dirty_log_create() as argc, leading to out-of-bounds argv array access. The fix reorders validation: param_count is checked against argc - 2 (safe since argc >= 2 is guaranteed) before the addition, preventing the overflow condition.

Defensive priority

medium

Recommended defensive actions

  • Apply kernel updates from stable branches when available (commits referenced in sourceItem metadata)
  • Restrict device mapper configuration privileges to trusted administrative accounts
  • Monitor for unusual device mapper table configurations in audit logs
  • Validate that systems using dm-mirror are running patched kernel versions

Evidence notes

CVE published 2026-05-27. Kernel.org stable branch commits provided as references. No CVSS score assigned by NVD at time of disclosure; status 'Awaiting Analysis'. Vendor identified as Kernel with low confidence per source metadata.

Official resources

2026-05-27