High

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 Dec 6, 2025 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+1
Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.18%

ahead of 7% of scored CVEs · Oct 15, 2026

Affects

Linux

CVSS base

7.8

High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ f0bd62b64016508938df9babe47f65c2c727d25c and < 98e9d5e33bda8db875cc1a4fe99c192658e45ab6version 5.8≥ 5.7.6 and < 5.7.8≥ 5.4.49 and < 5.4.51≥ 4.19.130 and < 4.19.132≥ 4.14.186 and < 4.14.188≥ 4.9.229 and < 4.9.230≥ 4.4.229 and < 4.4.230 and 12 more ≥ f0bd62b64016508938df9babe47f65c2c727d25c and < 05a1fc5efdd8560f34a3af39c9cf1e1526cc3ddf≥ f0bd62b64016508938df9babe47f65c2c727d25c and < d2c04f20ccc6c0d219e6d3038bab45bc66a178ad≥ 02c56650f3c118d3752122996d96173d26bb13aa and < 480a1490c595a242f27493a4544b3efb21b29f6a≥ f0bd62b64016508938df9babe47f65c2c727d25c and < ece3b981bb6620e47fac826a2156c090b1a936a0≥ f0bd62b64016508938df9babe47f65c2c727d25c and < ef592bf2232a2daa9fffa8881881fc9957ea56e9≥ f0bd62b64016508938df9babe47f65c2c727d25c and < 217d47255a2ec8b246f2725f5db9ac3f1d4109d7≥ f0bd62b64016508938df9babe47f65c2c727d25c and < 6a5da3fa80affc948923f20a4e086177f505e86e≥ d288dc74f8cf95cb7ae0aaf245b7128627a49bf3 and < d67dde02049e632ba58d3c44a164a74b6a737154≥ aba41867dd66939d336fdf604e4d73b805d8039f and < e0ed5a36fb3ab9e7b9ee45cd17f09f6d5f594360≥ 2d50acd7dbd0682a56968ad9551341d7fc5b6eaf and < c4dc012b027c9eb101583011089dea14d744e314≥ 99703c921864a318e3e8aae74fde071b1ff35bea and < 282aba56713bbc58155716b55ca7222b2d9cf3c8≥ 5ef30e443e6d3654cccecec99cf481a69a0a6d3b and < ab0b5e92fc36ee82c1bd01fe896d0f775ed5de41	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.8	CVSS 3.1	High	1.8	5.9	416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
7.8	CVSS 3.1	High	—	—	GitHub, Inc. via GitHub Security Advisories
7.8	CVSS 3.1	High	—	—	Linux via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.18%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.

endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · linux/linux
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 7.8
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Deferred
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
2025
CVE published
Dec 6, 2025 · Linux

Source activity

Repeated readings are counted rather than listed.

1× References added · Oct 15, 2026 – Oct 15, 2026
1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

15 on the record

git.kernel.org/stable/c/ab0b5e92fc36ee82c1bd01fe896d0f775ed5de41
NIST National Vulnerability Database
git.kernel.org/stable/c/6a5da3fa80affc948923f20a4e086177f505e86e
NIST National Vulnerability Database
git.kernel.org/stable/c/e0ed5a36fb3ab9e7b9ee45cd17f09f6d5f594360
NIST National Vulnerability Database
git.kernel.org/stable/c/05a1fc5efdd8560f34a3af39c9cf1e1526cc3ddf
NIST National Vulnerability Database
git.kernel.org/stable/c/282aba56713bbc58155716b55ca7222b2d9cf3c8
NIST National Vulnerability Database
git.kernel.org/stable/c/217d47255a2ec8b246f2725f5db9ac3f1d4109d7
NIST National Vulnerability Database
git.kernel.org/stable/c/c4dc012b027c9eb101583011089dea14d744e314
NIST National Vulnerability Database
git.kernel.org/stable/c/480a1490c595a242f27493a4544b3efb21b29f6a
NIST National Vulnerability Database
git.kernel.org/stable/c/d67dde02049e632ba58d3c44a164a74b6a737154
NIST National Vulnerability Database
git.kernel.org/stable/c/98e9d5e33bda8db875cc1a4fe99c192658e45ab6
NIST National Vulnerability Database
nvd.nist.gov/vuln/detail/CVE-2025-40269
GitHub Security Advisories
git.kernel.org/stable/c/ece3b981bb6620e47fac826a2156c090b1a936a0
NIST National Vulnerability Database
github.com/advisories/GHSA-7g56-9fh3-wcxw
GitHub Security Advisories
git.kernel.org/stable/c/ef592bf2232a2daa9fffa8881881fc9957ea56e9
NIST National Vulnerability Database
git.kernel.org/stable/c/d2c04f20ccc6c0d219e6d3038bab45bc66a178ad
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 8h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 8h
Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-40269 is "ALSA: usb-audio: Fix potential overflow of PCM transfer buffer", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.18% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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