medium CVSS 6.3 EPSS <0.1%

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

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at <0.1% — higher than 2% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

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

CVE-2026-63795CVSS 10In the Linux kernel, the following vulnerability has been resolved: 9p: avoid putting oldfid in p9_client_walk() error path When p9_client_walk() is called with clone set to false, fid aliases oldfid. If the walk subsequently fails after the request has been sent, the error path jumps to clunk_fid, which currently calls p9_fid_put(fid) unconditionally. This drops a reference to oldfid even though ownership of oldfid remains with the caller. If this is the last reference, oldfid can be clunked and destroyed while the caller still expects it to be valid. A later use or put of oldfid can then trigger a use-after-free or refcount underflow. Fix this by only putting fid in the clunk_fid error path when it does not alias oldfid, matching the existing guard in the error path below. This can be triggered when a multi-component walk is split into multiple p9_client_walk() calls and a later non-cloning walk fails. A reproducer and refcount warning logs are available on request.
CVE-2026-53221CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() In vti6_tnl_lookup(), when an exact match for a tunnel fails, the code falls back to searching for wildcard tunnels: - Tunnels matching the packet's local address, with any remote address wildcard remote). - Tunnels matching the packet's remote address, with any local address (wildcard local). However, vti6 stores all these different types of tunnels in the same hash table (ip6n->tnls_r_l) prone to hash collisions. The bug is that the fallback search loops in vti6_tnl_lookup() were missing checks to ensure that the candidate tunnel actually has a wildcard address.
CVE-2026-53151CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix the ACK parser to extract the SACK table for parsing Fix modification of the received skbuff in rxrpc_input_soft_acks() and a potential incorrect access of the buffer in a fragmented UDP packet (the packet would probably have to be deliberately pre-generated as fragmented) when AF_RXRPC tries to extract the contents of the SACK table by copying out the contents of the SACK table into a buffer before attempting to parse AF_RXRPC assumes that it can just call skb_condense() and then validly access the SACK table from skb->data and that it will be a flat buffer - but skb_condense() can silently fail to do anything under some circumstances. Note that whilst rxrpc_input_soft_acks() should be able to parse extended ACKs, the rest of AF_RXRPC doesn't currently support that. Further, there's then no need to call skb_condense() in rxrpc_input_ack(), so don't.
CVE-2026-53088CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: net: bcmgenet: fix off-by-one in bcmgenet_put_txcb The write_ptr points to the next open tx_cb. We want to return the tx_cb that gets rewinded, so we must rewind the pointer first then return the tx_cb that it points to. That way the txcb can be correctly cleaned up.
CVE-2026-53228CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ipv6: sit: reload inner IPv6 header after GSO offloads ipip6_tunnel_xmit() caches the inner IPv6 header pointer at function entry and continues using it after iptunnel_handle_offloads(). For GSO skbs, iptunnel_handle_offloads() calls skb_header_unclone(). When the skb header is cloned, skb_header_unclone() can call pskb_expand_head(), which may move the skb head. The pskb_expand_head() contract requires pointers into the skb header to be reloaded after the call. If the later skb_realloc_headroom() branch is not taken, SIT uses the stale iph6 pointer to read the inner hop limit and DS field. That can read from a freed skb head after the old head's remaining clone is released. Reload iph6 after the offload helper succeeds and before subsequent reads from the inner IPv6 header. Keep the existing reload after skb_realloc_headroom(), since that branch can also replace the skb.

References

Track CVEs across your fleet automatically

Defensia scans your Linux servers and tells you exactly which ones are running vulnerable versions — including CVE-2024-57893. Free for 1 server.

Get started free