SB2026093046 - Ubuntu update for linux-azure-fde-6.8
Published: September 30, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 9 vulnerabilities.
1) Use of uninitialized resource (CVE-ID: CVE-2026-46315)
CWE-ID: CWE-908 - Use of Uninitialized Resource
CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local user to disclose sensitive information.
The vulnerability exists due to uninitialized memory usage in io_uring IORING_OP_WAITID result handling when copying waitid result data to userspace. A local user can trigger a wait operation that completes without reporting a child event to disclose sensitive information.
The issue occurs because stale bytes from reused io_kiocb command storage may be copied to userspace siginfo when no child event information is written.
2) Use-after-free (CVE-ID: CVE-2026-46275)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to use-after-free in the hci_uart line discipline lifecycle management when closing or initializing a Bluetooth HCI UART device. A local user can trigger a hangup or race the close and initialization paths to cause a denial of service.
The issue involves workqueue handling and teardown ordering in the close and initialization error paths.
3) Improper resource shutdown or release (CVE-ID: CVE-2026-46170)
CWE-ID: CWE-404 - Improper Resource Shutdown or Release
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper resource shutdown or release in the mptcp path manager ADD_ADDR retransmission timer handling when processing ADD_ADDR retransmissions. A local user can trigger ADD_ADDR retransmissions to cause a system hang.
The issue occurs when the last socket reference is released from the timer handler, leading to an indefinite wait on the same timer.
4) Improper resource shutdown or release (CVE-ID: CVE-2026-46158)
CWE-ID: CWE-404 - Improper Resource Shutdown or Release
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper resource shutdown or release in the mptcp path manager ADD_ADDR retransmission handling when retransmitting ADD_ADDR messages. A local user can trigger ADD_ADDR retransmissions to cause a denial of service.
5) NULL pointer dereference (CVE-ID: CVE-2026-31560)
CWE-ID: CWE-476 - NULL Pointer Dereference
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a null pointer dereference in spi-dw-dma error logging when handling an error after a transaction finishes without a current message. A local user can trigger an error condition to cause a denial of service.
6) Race condition (CVE-ID: CVE-2026-31486)
CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a race condition in pmbus regulator operations when accessing PMBus registers and shared data. A local user can trigger concurrent regulator callbacks and voltage operations to cause a denial of service.
7) Improper input validation (CVE-ID: CVE-2026-31420)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper input validation in br_mrp_start_test(), br_mrp_start_in_test(), and br_mrp_start_in_test_parse() when processing user-supplied netlink attributes. A local user can supply a zero interval value to cause a denial of service.
A zero interval causes delayed work to be rescheduled with no delay, creating a tight loop that allocates and transmits MRP test frames until system memory is exhausted and the kernel panics via OOM deadlock.
8) Race condition (CVE-ID: CVE-2026-23469)
CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local attacker to cause a denial of service.
The vulnerability exists due to a race condition in the drm/imagination GPU driver interrupt handling during runtime power management suspend when suspending the GPU while an IRQ handler is still running on another CPU core. A local attacker can trigger GPU activity that races with runtime suspend to cause a denial of service.
This issue can lead to kernel crashes or a kernel panic when the IRQ handler accesses GPU registers while the GPU is suspended.
9) Improper Check or Handling of Exceptional Conditions (CVE-ID: CVE-2025-71289)
CWE-ID: CWE-703 - Improper Check or Handling of Exceptional Conditions
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper error handling in attr_set_size() during file truncation when truncating files on ntfs3. A local user can truncate a file in a way that triggers an attr_set_size() failure to cause a denial of service.
The inode may be left in an inconsistent state if the error is ignored.
Remediation
Install update from vendor's website.