CVE-2024-46777

What it actually does

The vulnerability stems from missing validation of UDF partition metadata, allowing partition lengths that overflow 32-bit block numbers or exceed safe bitmap indexing limits during mount.

Why it matters to the business

Attackers could cause kernel instability, crashes, or memory issues on systems that mount untrusted UDF filesystems, leading to downtime or potential data corruption in environments handling removable media or disk images.

How an attack unfolds

An attacker creates a malformed UDF filesystem image with an excessively large partition length, then delivers it via email, download, or physical media; when a user or automated process attempts to mount it, the kernel processes the unchecked values and encounters overflow or unsafe bitmap operations.

How to fix it

Apply the fix from commit c0c23130d38e8bc28e9ef581443de9b1fc749966 in the Linux kernel stable tree; rebuild and deploy updated kernels across affected systems. Where possible, disable UDF filesystem support or restrict mounts to trusted sources only.

How to confirm the fix worked

Verify the presence of commit c0c23130d38e8bc28e9ef581443de9b1fc749966 in the running kernel source or binary; test by attempting to mount a crafted UDF image with oversized partitions and confirm rejection before mount proceeds.

Typical attack path

1. Craft a UDF image containing partition metadata that exceeds 32-bit block limits or bitmap safety thresholds
2. Distribute the image to the target environment
3. Induce mounting of the image through user action or automated script
4. Trigger kernel processing of the invalid partition data resulting in overflow or indexing errors

How to detect it

Monitor kernel logs for UDF-related mount failures, warnings about partition length, or oops/panic messages during filesystem attachment; correlate with processes attempting to mount removable media or disk images.

What your security team should do

• Prioritize kernel updates containing the referenced commit on all Linux systems that may process UDF media
• Implement mount options or policy to block UDF on untrusted volumes
• Review logging configurations to capture UDF mount attempts and kernel errors