Freed-memory access via unserialized compat port creation
Published Oct 18, 2026 · Updated Oct 18, 2026
Use-after-free in Linux ALSA sequencer compat ioctls allows local users to access freed kernel memory via racing requests. snd_seq_call_port_info_ioctl dispatches converted requests without client->ioctl_mutex, letting concurrent CREATE_PORT calls exceed the port limit and wrap addresses so subscriber teardown selects the wrong port. Access requires a usable ALSA sequencer compat interface; the disclosed consequence is freed-subscriber access, with no demonstrated privilege escalation or data disclosure.
Summary
What happened
Use-after-free in Linux ALSA sequencer compat ioctls allows local users to access freed kernel memory via racing requests. snd_seq_call_port_info_ioctl dispatches converted requests without client->ioctl_mutex, letting concurrent CREATE_PORT calls exceed the port limit and wrap addresses so subscriber teardown selects the wrong port. Access requires a usable ALSA sequencer compat interface; the disclosed consequence is freed-subscriber access, with no demonstrated privilege escalation or data disclosure.
The record
- CVE
- CVE-2026-98742
- Published
- Oct 18, 2026
- Updated
- Oct 18, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Oct 18, 2026CVE publishedPublication date reported by the CVE source.
- Oct 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=02cbce8576a31df8fca54aaec91ee081076bd79d
- Affected versionversion=3.16.54 <3.17
- Affected versionversion=3.18.94 <3.19
- Affected versionversion=3.2.99 <3.3
- Affected versionversion=4.14.15 <4.15
- Affected versionversion=4.15
- Affected versionversion=4.1.50 <4.2
- Affected versionversion=4.4.115 <4.5
- Affected versionversion=4.9.78 <4.10
- Affected versionversion=623e5c8ae32b39cc8baea83478695dc624935318
- Affected versionversion=6aab3aa52366a0051e5abf8aae4616c42053fd8e
- Affected versionversion=b3defb791b26ea0683a93a4f49c77ec45ec96f10 <413211dd31cb2ef2fc99fb0aa1a037a97509502c
- Affected versionversion=b3defb791b26ea0683a93a4f49c77ec45ec96f10 <702d92f361f65d9698c473c7599d471395dc4341
- Affected versionversion=b3defb791b26ea0683a93a4f49c77ec45ec96f10 <95b2e0361c88753afa030c10698be0a1a5b67650
- Affected versionversion=b3defb791b26ea0683a93a4f49c77ec45ec96f10 <fc5c52848e405b6efb073db5035bb9ebaed11ec4
- Affected versionversion=c3162384aed4cfe3f1a1f40041f3ba8cd7704d88
- Affected versionversion=d6693160906d55ba376bf0b88b7c129762170162
- Affected versionversion=e4ff9f294629b65df3f7982cd4faf86b2856b9d7
- Affected versionversion=f8a38ab4cd9624fc5ac8a7f965c7b20f5b62c03c
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
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Public exploit references
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Technologies
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