CVE-2025-40269 | ALSA: usb-audio: Fix potential overflow of PCM transfer buffer

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Fix potential overflow of PCM transfer buffer The PCM stream data in USB-audio driver is transferred over USB URB packet buffers, and each packet size is determined dynamically. The packet sizes are limited by some factors such as wMaxPacketSize USB descriptor. OTOH, in the current code, the actually used packet sizes are determined only by the rate and the PPS, which may be bigger than the size limit above. This results in a buffer overflow, as reported by syzbot. Basically when the limit is smaller than the calculated packet size, it implies that something is wrong, most likely a weird USB descriptor. So the best option would be just to return an error at the parameter setup time before doing any further operations. This patch introduces such a sanity check, and returns -EINVAL when the packet size is greater than maxpacksize. The comparison with ep->packsize[1] alone should suffice since it's always equal or greater than ep->packsize[0].

Published: 2025-12-06 Last update: 2026-04-15 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Conclusion & alert: CVE-2025-40269 is rated Moderate Risk (43.1/100): low exploitation likelihood (EPSS 0.21%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-40269

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-16 0.14% 0.21% +0.07%
2 2026-05-04 0.18% 0.14% -0.04%
3 2026-01-18 0.18%

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-40269

CVSS metrics for this CVE.

No CVSS data in dataset for this CVE.

Weakness enumeration for CVE-2025-40269

OS Trackers for CVE-2025-40269

vendor priority summary link
debian not yet assigned CVE-2025-40269 not yet assigned priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. https://security-tracker.debian.org/tracker/CVE-2025-40269
redhat medium https://access.redhat.com/security/cve/CVE-2025-40269
suse medium CVE-2025-40269 severity moderate: SUSE including 535 source package names (13.2-9.1:libsystemd0-254.23-1.1, 13.2-9.1:libudev1-254.23-1.1, …), 1064 product×package rows across 183 product lines (Container suse/sl-micro/6.0/baremetal-os-container, Container suse/sl-micro/6.0/base-os-container, … (183 product lines)): Fixed 765, Known Affected 231, Known Not Affected 43, First Fixed 25. https://www.suse.com/security/cve/CVE-2025-40269/
ubuntu medium CVE-2025-40269 medium priority: Ubuntu including 157 source packages (linux, linux-allwinner-5.19, …), 1405 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): DNE 1010, ignored 182, released 157, needed 50, not-affected 3, pending 3. https://ubuntu.com/security/CVE-2025-40269

Affected software / configurations for CVE-2025-40269

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-40269

URL Tags
https://git.kernel.org/stable/c/05a1fc5efdd8560f34a3af39c9cf1e1526cc3ddf
https://git.kernel.org/stable/c/217d47255a2ec8b246f2725f5db9ac3f1d4109d7
https://git.kernel.org/stable/c/282aba56713bbc58155716b55ca7222b2d9cf3c8
https://git.kernel.org/stable/c/480a1490c595a242f27493a4544b3efb21b29f6a
https://git.kernel.org/stable/c/6a5da3fa80affc948923f20a4e086177f505e86e
https://git.kernel.org/stable/c/98e9d5e33bda8db875cc1a4fe99c192658e45ab6
https://git.kernel.org/stable/c/ab0b5e92fc36ee82c1bd01fe896d0f775ed5de41
https://git.kernel.org/stable/c/c4dc012b027c9eb101583011089dea14d744e314
https://git.kernel.org/stable/c/d2c04f20ccc6c0d219e6d3038bab45bc66a178ad
https://git.kernel.org/stable/c/d67dde02049e632ba58d3c44a164a74b6a737154
https://git.kernel.org/stable/c/e0ed5a36fb3ab9e7b9ee45cd17f09f6d5f594360
https://git.kernel.org/stable/c/ece3b981bb6620e47fac826a2156c090b1a936a0
https://git.kernel.org/stable/c/ef592bf2232a2daa9fffa8881881fc9957ea56e9
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