CVE-2026-68184 cdrom: fix stack out-of-bounds read in CDROMVOLCTRL

Not scored Published 10 Aug 2026 Updated 19 Aug 2026

A local attacker with access to CD-ROM devices can trigger a stack out-of-bounds read in the Linux kernel, potentially leaking memory or causing a crash.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2026-68184?

CVE-2026-68184 is a memory corruption vulnerability in Linux, published on 10 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

cdrom: fix stack out-of-bounds read in CDROMVOLCTRL

mmc_ioctl_cdrom_volume() first reads the audio control mode page into a 32-byte stack buffer with cgc->buflen set to 24. If the device reports a block descriptor, the function increases cgc->buflen to include that descriptor and reads the page again.

For CDROMVOLCTRL, the function then builds a MODE SELECT parameter list by moving cgc->buffer forward by offset - 8 bytes. This drops the block descriptor from the outgoing payload and leaves a new 8-byte mode parameter header in front of the audio control page. However, cgc->buflen is left unchanged.

With a standard 8-byte block descriptor, cgc->buffer points at buffer + 8 but cgc->buflen remains 32. cdrom_mode_select() therefore asks the low level packet path to write 32 bytes from that adjusted pointer, reading 8 bytes past the end of the 32-byte stack buffer.

This is not hit by CDROMVOLREAD, and CDROMVOLCTRL only triggers it on drives that return a non-zero block descriptor length, which helps explain why it has gone unnoticed. The overread is also sent to the device as extra MODE SELECT payload, so it may not produce an obvious local failure.

Reduce cgc->buflen by the same amount as the buffer pointer adjustment so the MODE SELECT transfer covers only the intended parameter list.

Which versions are affected by CVE-2026-68184?

How do I fix CVE-2026-68184?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-68184 being exploited?

There is no known exploitation of CVE-2026-68184 in the wild and no public exploit code.

Sources

Also known as BELL-CVE-2026-68184, DEBIAN-CVE-2026-68184, GHSA-j56f-w52c-9vh2, UBUNTU-CVE-2026-68184.