medium CVSS 6.3

CVE-2024-57893·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: oss: Fix races at processing SysEx messages OSS sequencer handles the SysEx messages split in 6 bytes packets, and ALSA sequencer OSS layer tries to combine those. It stores the data in the internal buffer and this access is racy as of now, which may lead to the out-of-bounds access. As a temporary band-aid fix, introduce a mutex for serializing the process of the SysEx message packets.

Severity
medium
Software
Kernel
Fixed in
6.12.9
Published
2025-01-15

Affected versions

From: 6.7

Until: 6.12.9

Fixed in: 6.12.9

How to fix this CVE

Update your Linux kernel to version 6.12.9 or later to resolve a race condition in the ALSA sequencer OSS layer that processes MIDI SysEx messages. This vulnerability allows a local user with ALSA privileges to trigger out-of-bounds memory access by exploiting concurrent access to shared SysEx packet buffers. Applying the kernel update will patch the synchronization mechanism that protects these buffers.

sudo dnf check-update kernel && sudo dnf update kernel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check your current kernel version with `uname -r` and verify it is between 6.7.x and 6.12.8 inclusive
  2. Step 2: Verify ALSA sequencer OSS support is loaded by running `lsmod | grep snd_seq_oss`
  3. Step 3: Search system logs for SysEx-related errors with `sudo journalctl -xe | grep -i sysex` or `sudo grep -i sysex /var/log/kern.log`
  4. Step 4: After patching, confirm the new kernel version with `uname -r` and verify it shows 6.12.9 or later, then reboot to activate

FAQ

What is CVE-2024-57893?

CVE-2024-57893 is a race condition in the Linux kernel's ALSA sequencer OSS layer that improperly handles MIDI SysEx message fragments. When multiple processes access the internal SysEx buffer concurrently, an out-of-bounds memory read or write can occur, potentially causing kernel crashes or privilege escalation.

Is CVE-2024-57893 being actively exploited?

No, CVE-2024-57893 is not listed on the CISA Known Exploited Vulnerabilities catalog and no public exploits have been released. However, it requires local access with ALSA privileges to trigger.

What versions of Kernel are affected by CVE-2024-57893?

Linux kernel versions 6.7.0 through 6.12.8 are vulnerable. Version 6.12.9 and later contain the fix.

How do I check if my server is vulnerable to CVE-2024-57893?

Run `uname -r` to display your kernel version. If the output shows 6.7.x through 6.12.8, your system is vulnerable. Cross-reference against your distribution's security advisories for exact patched versions.

Does Defensia detect CVE-2024-57893?

Yes — Defensia's CVE advisory scanner compares installed kernel package versions against the NVD database. If a vulnerable kernel version is detected on a monitored server, CVE-2024-57893 will appear in your dashboard with remediation steps.

Related Kernel CVEs

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CVE-2026-64383CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_flush() replay SMB2_flush() keeps its response buffer bookkeeping across replay attempts. If a replayable flush response is received and the retry then fails before cifs_send_recv() stores a replacement response, flush_exit will free the stale response pointer a second time. Reinitialize resp_buftype and rsp_iov at the top of the replay loop so cleanup only acts on response state produced by the current attempt. This fixes a double-free without changing replay handling for successful requests.
CVE-2026-64385CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_ioctl() replay A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_ioctl_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.
CVE-2026-64384CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: fix change notify replay double-free A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_notify_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.

References

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