Race condition in Linux kernel ALSA sequencer compat port ioctls
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 1 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel ALSA sequencer compat port-info ioctl path calls its handlers without the ioctl mutex that the native path takes. Concurrent compat CREATE_PORT requests can make the computed port index wrap to an existing index, and later subscriber teardown can then access a freed subscriber.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Serialize compat port-info ioctls The native sequencer ioctl path serializes handler calls with client->ioctl_mutex, but the translated port-info compat path invokes the same handlers through snd_seq_kernel_client_ctl() without taking that mutex. This lets concurrent compat CREATE_PORT requests pass the port-count check before any request reaches the serialized insertion. The computed integer port index can then exceed the address field range and wrap to an existing index. Subsequent subscriber teardown can resolve the duplicate address to the wrong port and access a freed subscriber. Take ioctl_mutex while dispatching converted port-info requests, matching the native ioctl path. All translated port-info commands share this helper, so their accesses to the client port state are serialized as well.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 3.2.99 to before 3.3; 3.16.54 to before 3.17; 3.18.94 to before 3.19; 4.1.50 to before 4.2; 4.4.115 to before 4.5; 4.9.78 to before 4.10; 4.14.15 to before 4.15 | 3.3, 3.17, 3.19, 4.2, 4.5, 4.10, 4.15 | Patch available | CNA |
| Linux | Linux | 4.15 and later | 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 3.2.99 to before 3.3; 3.16.54 to before 3.17; 3.18.94 to before 3.19; 4.1.50 to before 4.2; 4.4.115 to before 4.5; 4.9.78 to before 4.10; 4.14.15 to before 4.15 Fixed in 3.3, 3.17, 3.19, 4.2, 4.5, 4.10, 4.15 Patch available CNA
- Linux VendorLinux Affected 4.15 and later Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3 Patch available CNA
Remediation
Update the Linux kernel to a fixed version for its branch: 3.3, 3.17, 3.19, 4.2, 4.5, 4.10, 4.15, 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10 or 7.3. Red Hat lists Red Hat Enterprise Linux 10 as affected with no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
- Fix · CNA Linux (Linux) Fixed in 3.3, 3.17, 3.19, 4.2, 4.5, 4.10, 4.15
- Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-18 Threatist record created from CVE-2026-98742
- 2026-10-18 Alias added: GHSA-qq2g-8h6m-jjjf
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Affected versions changed · Red Hat
- 2026-10-21 CVSS score added · Red Hat
- 2026-10-21 Fix available: Linux/Linux@2db234e163f0d211b69a4eebbec8aacc5a54a80e, Linux/[email protected] · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-30 Fix available: Linux/Linux@14e178c60ba1cea49186fcfccac93d66aa94e9e0, Linux/Linux@2c0cce3a5a660270d65729b0f318d4e01470479d, Linux/Linux@4980768c5d092493be0deb20d1ee86aa661466f8 +3 · CNA
- 2026-10-30 3 new references · CNA
References
Other 8
- https://git.kernel.org/stable/c/14e178c60ba1cea49186fcfccac93d66aa94e9e0
- https://git.kernel.org/stable/c/4980768c5d092493be0deb20d1ee86aa661466f8
- https://git.kernel.org/stable/c/2c0cce3a5a660270d65729b0f318d4e01470479d
- https://git.kernel.org/stable/c/2db234e163f0d211b69a4eebbec8aacc5a54a80e
- https://git.kernel.org/stable/c/413211dd31cb2ef2fc99fb0aa1a037a97509502c
- https://git.kernel.org/stable/c/fc5c52848e405b6efb073db5035bb9ebaed11ec4
- https://git.kernel.org/stable/c/702d92f361f65d9698c473c7599d471395dc4341
- https://git.kernel.org/stable/c/95b2e0361c88753afa030c10698be0a1a5b67650
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Sources
- CVE-2026-98742 · CVE Program
- CVE-2026-98742 · NVD
- FIRST EPSS
- GHSA-qq2g-8h6m-jjjf · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98742 · Red Hat security data · CC BY 4.0
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