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CVE Record

CVE-2025-39757: ALSA: usb-audio: Validate UAC3 cluster segment descriptors

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Validate UAC3 cluster segment descriptors UAC3 class segment descriptors need to be verified whether their sizes match with the declared lengths and whether they fit with the allocated buffer sizes, too. Otherwise malicious firmware may lead to the unexpected OOB accesses.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2025-39757 is a Linux kernel USB audio flaw. A malicious USB audio device or firmware could provide malformed UAC3 audio descriptors and trigger out-of-bounds memory access. Business risk is highest for systems where users, peripherals, or embedded components can introduce USB audio hardware.

Executive priority

Treat as a planned kernel update with higher urgency for physically accessible systems and products accepting USB peripherals. There is no cited active exploitation, but malformed device firmware can cross a hardware trust boundary into kernel memory handling.

Technical view

The ALSA usb-audio driver did not sufficiently validate UAC3 cluster segment descriptor sizes against declared lengths and allocated buffers. The Linux fix adds bounds validation to prevent unexpected out-of-bounds accesses. Public sources do not provide CVSS, CWE, confirmed impact beyond OOB access, or active exploitation evidence.

Likely exposure

Linux systems with affected kernel builds and USB audio support are potentially exposed when parsing UAC3 USB audio device descriptors. Exposure is more practical on endpoints, kiosks, labs, embedded systems, or appliances that accept physical USB peripherals. Distro and vendor backports may change exact exposure.

Exploitation context

Sources describe malicious firmware as the trigger. That implies attacker influence over a USB audio device or equivalent device-emulation path. CISA KEV is false in the provided data, and no cited source confirms active exploitation.

Researcher notes

The key issue is descriptor length and buffer-size validation in ALSA usb-audio UAC3 cluster segment parsing. The CVE record lists multiple Linux stable commit references. Exact affected-version semantics are incomplete in the bundle, so use vendor package advisories for final applicability.

Mitigation direction

  • Apply vendor or distribution kernel updates that include the referenced stable fixes.
  • Review Debian LTS advisories if running affected Debian LTS kernels.
  • Restrict use of untrusted USB audio devices on sensitive Linux systems.
  • For Siemens environments, check the Siemens ProductCERT advisory for product-specific guidance.

Validation and detection

  • Inventory Linux kernel versions and package backport status across exposed systems.
  • Confirm whether ALSA usb-audio and USB peripheral access are present or needed.
  • Map kernels to vendor advisories or the referenced upstream stable commits.
  • Review logs for unusual USB audio enumeration failures or kernel memory errors.
Prepared
Confidence
medium
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2025-39757 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
3ADP providers
13Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
siemens-SADPADP container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux11785ef53228d23ec386f5fe4a34601536f0c891, 11785ef53228d23ec386f5fe4a34601536f0c891, 11785ef53228d23ec386f5fe4a34601536f0c891, 11785ef53228d23ec386f5fe4a34601536f0c891, 11785ef53228d23ec386f5fe4a34601536f0c891, 11785ef53228d23ec386f5fe4a34601536f0c891, 11785ef53228d23ec386f5fe4a34601536f0c891, 11785ef53228d23ec386f5fe4a34601536f0c891, 11785ef53228d23ec386f5fe4a34601536f0c891unaffected
LinuxLinux4.19, 0, 5.4.297, 5.10.241, 5.15.190, 6.1.149, 6.6.103, 6.12.43, 6.15.11, 6.16.2, 6.17affected
Weakness

CWE details

No CWE listed

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