high CVSS 7.1 Actively exploited EPSS 0.93%

CVE-2024-53150·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Fix out of bounds reads when finding clock sources The current USB-audio driver code doesn't check bLength of each descriptor at traversing for clock descriptors. That is, when a device provides a bogus descriptor with a shorter bLength, the driver might hit out-of-bounds reads. For addressing it, this patch adds sanity checks to the validator functions for the clock descriptor traversal. When the descriptor length is shorter than expected, it's skipped in the loop. For the clock source and clock multiplier descriptors, we can just check bLength against the sizeof() of each descriptor type. OTOH, the clock selector descriptor of UAC2 and UAC3 has an array of bNrInPins elements and two more fields at its tail, hence those have to be checked in addition to the sizeof() check.

Severity
high
Software
Kernel
Fixed in
6.12.2
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 0.93% — higher than 76% 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.

Read the two together. CVE-2024-53150 scores 7.1 on CVSS, so a successful attack would be serious — but at 0.93%, almost nobody is currently attempting it. That is a different situation from a flaw under mass exploitation, and it is usually the difference between patching on your next maintenance window and patching tonight.

Affected versions

From: 6.12

Until: 6.12.2

Fixed in: 6.12.2

How to fix this CVE

Update the Linux kernel to a patched version. Blacklist the snd-usb-audio module on servers that do not use USB audio. Restrict physical USB access.

# Immediate mitigation without reboot:
sudo modprobe -r snd-usb-audio 2>/dev/null
echo 'blacklist snd-usb-audio' | sudo tee /etc/modprobe.d/blacklist-usb-audio.conf

Defensia detects this vulnerability

What an exploitation attempt looks like

Sample log line indicative of exploitation attempts:

Physical access attack via malicious USB audio device. A crafted device provides USB audio descriptors with invalid bLength fields for clock source entries. When the kernel parses these descriptors to find clock sources, it reads beyond the descriptor buffer, leaking kernel heap memory. This leaked data can defeat KASLR and enable further exploitation.

WAF mitigation (if patching is not yet possible)

Add this rule to your WAF to block exploitation attempts while you schedule the patch. 

WAF cannot mitigate USB-level kernel vulnerabilities. Compensating controls: blacklist snd-usb-audio, deploy USBGuard, disable unused USB ports in BIOS, restrict physical access, and maintain rapid kernel patching.

How to check if you are affected

  1. Check kernel version against security advisories for your distribution
  2. Check if snd-usb-audio is loaded: lsmod | grep snd_usb_audio
  3. Monitor dmesg for USB audio parsing errors: dmesg | grep -i 'usb.*audio\|clock.*source'
  4. Verify USBGuard status: systemctl status usbguard 2>/dev/null
  5. Check USB authorization: find /sys/bus/usb/devices -name authorized -exec cat {} \;

Indicators of compromise

  • USB audio devices with malformed clock source descriptors in kernel logs
  • KASAN reports mentioning usb-audio clock source parsing functions
  • Unexpected snd-usb-audio module loads on headless servers
  • Kernel heap information leaks correlated with USB device insertion events

FAQ

How does this differ from CVE-2024-53197?

Both are in the USB audio driver, but this CVE is an out-of-bounds read (information leak) in clock source parsing, while CVE-2024-53197 is an out-of-bounds access in configuration parsing for specific devices. They have similar mitigations — blacklisting snd-usb-audio addresses both.

Can information leaks alone compromise a server?

Not directly, but information leaks that reveal kernel memory layout (defeating KASLR) are critical building blocks for kernel exploitation chains. This is why CISA KEV lists it despite being 'only' an information disclosure.

Does blacklisting snd-usb-audio fix both CVE-2024-53150 and CVE-2024-53197?

Yes. Both vulnerabilities are in the snd-usb-audio module. Blacklisting it prevents the vulnerable code from loading, mitigating both CVEs simultaneously.

Are containers or VMs affected?

Only if USB device passthrough is configured. Standard containers and VMs without USB access are not affected.

Is this being exploited in the wild?

Yes. Its inclusion in CISA KEV indicates active exploitation, likely as part of targeted attack chains that combine information disclosure with privilege escalation vulnerabilities.

Related Kernel CVEs

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CVE-2026-64125CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: net: bcmgenet: keep RBUF EEE/PM disabled Setting RBUF_EEE_EN | RBUF_PM_EN in RBUF_ENERGY_CTRL breaks the RX path on GENET hardware once MAC EEE becomes active. RX traffic stops flowing while the link stays up and the usual descriptor/RX error counters remain quiet. In that state the MAC still accepts frames (rbuf_ovflow_cnt keeps climbing) but RBUF no longer forwards them to DMA, so rx_packets is no longer incremented at the netdev level. On some boards the corruption ends up as a paging fault in skb_release_data via bcmgenet_rx_poll on an LPI exit. Reproduced on Pi 4B (BCM2711 + BCM54213PE) and confirmed by Florian Fainelli on an internal Broadcom 4908-family board with the same crash signature. RBUF_PM_EN is not publicly documented. This shows up more often now that phy_support_eee() enables EEE by default, but it also affects older kernels as soon as TX LPI is turned on via ethtool, so it is not specific to recent changes. Always clear RBUF_EEE_EN | RBUF_PM_EN in bcmgenet_eee_enable_set so the bits stay off across resets. UMAC and TBUF setup is left alone so TX-side EEE keeps working.
CVE-2026-64136CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked() Commit 96c4af418586 ("cifs: Fix locking usage for tcon fields") refactored cifs code to change cifs_tcp_ses_lock for tc_lock around tc_count changes. There was missing lock around tc_count increment inside smb2_find_smb_sess_tcon_unlocked().
CVE-2026-53399CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: nfsd: release layout stid on setlease failure nfs4_alloc_stid() publishes the new stid into cl->cl_stateids via idr_alloc_cyclic() under cl_lock before returning to nfsd4_alloc_layout_stateid(). When nfsd4_layout_setlease() then fails, the error path frees the layout stateid directly with kmem_cache_free() without ever calling idr_remove(), leaving the IDR slot pointing at freed slab memory. Any subsequent IDR walker (states_show, client teardown) dereferences the dangling pointer. The correct teardown for an IDR-published stid is nfs4_put_stid(), which removes the IDR slot under cl_lock, dispatches sc_free (nfsd4_free_layout_stateid) to release ls->ls_file via nfsd4_close_layout(), and drops the nfs4_file reference in its tail. A second issue blocks that switch: nfsd4_free_layout_stateid() unconditionally inspects ls->ls_fence_work via delayed_work_pending() under ls_lock, but INIT_DELAYED_WORK(&ls->ls_fence_work, ...) currently runs only after the setlease call. On the setlease-failure path the destructor would touch an uninitialized delayed_work. nfsd4_alloc_layout_stateid() nfs4_alloc_stid() /* idr_alloc_cyclic under cl_lock */ nfsd4_layout_setlease() /* fails */ nfs4_put_stid() nfsd4_free_layout_stateid() delayed_work_pending(&ls->ls_fence_work) /* needs INIT */ nfsd4_close_layout() /* nfsd_file_put(ls->ls_file) */ put_nfs4_file() Fix by hoisting the ls_fenced / ls_fence_delay / INIT_DELAYED_WORK initialization above the nfsd4_layout_setlease() call, and replace the manual nfsd_file_put + put_nfs4_file + kmem_cache_free cleanup with a single nfs4_put_stid(stp).

References

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