SB20261111181 - Ubuntu update for linux, linux-aws, linux-aws-5.15 and more

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Main Vulnerability Database SB20261111181

SB20261111181 - Ubuntu update for linux, linux-aws, linux-aws-5.15 and more

Published: November 11, 2026

Security Bulletin ID SB20261111181
CSH Severity
High
Patch available
YES
Number of vulnerabilities 6
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

High 17% Medium 17% Low 67%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 6 vulnerabilities.


1) Use of uninitialized resource (CVE-ID: CVE-2025-21656)

CWE-ID: CWE-908 - Use of Uninitialized Resource

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 perform a denial of service (DoS) attack.

The vulnerability exists due to use of uninitialized resource within the drivetemp_scsi_command() function in drivers/hwmon/drivetemp.c. A local user can perform a denial of service (DoS) attack.


2) Integer underflow (CVE-ID: CVE-2026-63940)

CWE-ID: CWE-191 - Integer underflow

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 an integer underflow in KVM SEV Port I/O handling in arch/x86/kvm/svm/sev.c when processing Port I/O requests with a length or count of 0. A local user can trigger a zero-length Port I/O request to cause a denial of service.

The issue affects the handling of VMGEXIT and string I/O requests in the KVM SEV implementation.


3) Out-of-bounds read (CVE-ID: CVE-2026-74350)

CWE-ID: CWE-125 - Out-of-bounds read

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 an out-of-bounds read in the ocfs2 fast symlink read path when processing a malformed zero-cluster symlink inode. A local user can provide a crafted filesystem image containing an invalid fast symlink to disclose sensitive information.

The issue is triggered when the inline symlink payload is not NUL-terminated at the recorded size or when the recorded size exceeds the inline fast-symlink capacity.


4) Use-after-free (CVE-ID: CVE-2026-98432)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to potentially cause a denial of service through access to freed IPv6 request socket options.

The vulnerability exists due to use-after-free in tcp_v6_reqsk_destructor() when request socket migration leaves concurrent processing using shared options after they have been freed. A remote attacker can send TCP traffic that encounters concurrent request socket migration and destruction to potentially cause a kernel crash.

The affected ipv6_opt options are only set by CALIPSO.


5) Use-after-free (CVE-ID: CVE-2026-98432)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 9.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to use-after-free in the Linux kernel IPv4 TCP socket option handling when socket destruction frees shared options while another CPU is still using them to build a SYNACK or create a child socket. A remote attacker can send TCP traffic that encounters these concurrent processing paths to potentially cause a kernel crash.

The request socket migration path requires net.ipv4.tcp_migrate_req=1 or a BPF_SK_REUSEPORT_SELECT_OR_MIGRATE program. IPv6 is not affected by the child socket ownership-transfer path because it duplicates the options.


6) Improper input validation (CVE-ID: CVE-2026-99999)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to corrupt IPv4 packet headers and potentially compromise system confidentiality, integrity, and availability.

The vulnerability exists due to improper validation of the checksum start offset in the Linux kernel IPv4 checksum-completion paths when processing packets with invalid checksum metadata. A remote attacker can introduce a packet whose checksum start offset precedes the end of its IPv4 header into an affected processing path to cause skb_checksum_help to corrupt the network header, potentially compromising system confidentiality, integrity, and availability.


Remediation

Install update from vendor's website.

References