VulnerabilityPublished 25 Jul 2026

CVE-2026-64487: Linux kernel · ALSA: caiaq: fix out-of-bounds read in the Traktor Kontrol S4 input parser

Source GCVE Database

Not known to be exploited.

Data as of 26 Oct 2026, 14:05 UTC

Severity

Medium

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-x4v5-hfh7-vrg5

What to do

AI-suggested

A fix has been implemented in the Linux kernel to address this issue by modifying the input parser to process only complete 16-byte message blocks, preventing the out-of-bounds read. Users should apply the official Linux kernel updates that include this patch. Since this is a kernel-level vulnerability, updating the kernel to a fixed version is the recommended remediation. Patch status is not explicitly stated in the provided data; users should consult the vendor or Linux kernel advisory for the exact fixed versions and update accordingly.

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: caiaq: fix out-of-bounds read in the Traktor Kontrol S4 input parser snd_usb_caiaq_tks4_dispatch() decodes the Traktor Kontrol S4 input stream in fixed 16-byte (TKS4_MSGBLOCK_SIZE) message blocks. On every iteration it advances buf and subtracts the block size while looping on "while (len)". len is urb->actual_length. That value is supplied by the device and is not guaranteed to be a multiple of 16. When a final short block leaves len between 1 and 15, the loop runs once more, reads up to buf[15], and then does "len -= TKS4_MSGBLOCK_SIZE". As len is unsigned this underflows to a huge value. The loop then keeps iterating and walking buf far past the end of the 512-byte ep4_in_buf, reading out of bounds until a bogus block id happens to be hit. Iterate only while a full message block is available. This stops the unsigned underflow and silently drops any trailing partial block, which carries no complete control value anyway. The sibling endpoint-4 parsers are not affected. The Traktor Kontrol X1 and Maschine arms in snd_usb_caiaq_ep4_reply_dispatch() floor urb->actual_length before dispatching.

Impact

The vulnerability allows an out-of-bounds read in kernel memory, which could potentially lead to information disclosure or kernel instability. However, no specific exploit or active exploitation in the wild is reported. The impact is limited to the ALSA caiaq driver handling the Traktor Kontrol S4 input stream.

Summary

The Linux kernel ALSA caiaq driver function snd_usb_caiaq_tks4_dispatch() processes input streams from the Traktor Kontrol S4 device in fixed 16-byte blocks. The vulnerability arises because the length of the input data (urb->actual_length) is device-supplied and may not be a multiple of 16. When a final partial block of 1 to 15 bytes is present, the loop incorrectly continues, causing an unsigned underflow of the length variable and reading beyond the allocated 512-byte buffer. This results in an out-of-bounds read until an invalid block ID is encountered. The fix involves iterating only while a full 16-byte block is available, preventing the underflow and ignoring incomplete trailing data. Other related parsers for sibling endpoints are unaffected.

References

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