USN-7939-2 Unknown

USN-7939-2: Linux kernel (Azure FIPS) vulnerabilities

Canonical (Ubuntu) Released: December 16, 2025 Updated: December 22, 2025 Restart Required

Description

Jean-Claude Graf, Sandro Rüegge, Ali Hajiabadi, and Kaveh Razavi discovered that the Linux kernel contained insufficient branch predictor isolation between a guest and a userspace hypervisor for certain processors. This flaw is known as VMSCAPE. An attacker in a guest VM could possibly use this to expose sensitive information from the host OS. (CVE-2025-40300) Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - Cryptographic API; - ACPI drivers; - HSI subsystem; - I3C subsystem; - InfiniBand drivers; - Media drivers; - Network drivers; - Pin controllers subsystem; - AFS file system; - F2FS file system; - SMB network file system; - Padata parallel execution mechanism; - Timer subsystem; - Tracing infrastructure; - Memory management; - Appletalk network protocol; - Networking core; - Netfilter; (CVE-2022-49026, CVE-2022-49390, CVE-2023-52854, CVE-2024-35867, CVE-2024-47691, CVE-2024-49935, CVE-2024-50061, CVE-2024-50067, CVE-2024-50095, CVE-2024-50196, CVE-2024-53090, CVE-2024-53218, CVE-2024-56664, CVE-2025-21727, CVE-2025-21855, CVE-2025-37838, CVE-2025-37958, CVE-2025-38352, CVE-2025-38666, CVE-2025-39964, CVE-2025-39993, CVE-2025-40018)

Fixed Vulnerabilities 10

CVE-2025-40300 N/A 0.0 ⚠️ KEV fixed

Sep 11, 2025

In the Linux kernel, the following vulnerability has been resolved: x86/vmscape: Add conditional IBPB mitigation VMSCAPE is a vulnerability that exploits insufficient branch predictor isolation…

CVE-2025-21855 N/A 0.0 ⚠️ KEV fixed

Mar 12, 2025

In the Linux kernel, the following vulnerability has been resolved: ibmvnic: Don't reference skb after sending to VIOS Previously, after successfully flushing the xmit buffer…

CVE-2025-21727 N/A 0.0 ⚠️ KEV fixed

Feb 27, 2025

In the Linux kernel, the following vulnerability has been resolved: padata: fix UAF in padata_reorder A bug was found when run ltp test: BUG: KASAN:…

CVE-2022-49390 N/A 0.0 ⚠️ KEV fixed

Feb 26, 2025

In the Linux kernel, the following vulnerability has been resolved: macsec: fix UAF bug for real_dev Create a new macsec device but not get reference…

CVE-2025-37958 N/A 0.0 ⚠️ KEV fixed

May 20, 2025

In the Linux kernel, the following vulnerability has been resolved: mm/huge_memory: fix dereferencing invalid pmd migration entry When migrating a THP, concurrent access to the…

CVE-2025-38666 N/A 0.0 ⚠️ KEV fixed

Aug 22, 2025

In the Linux kernel, the following vulnerability has been resolved: net: appletalk: Fix use-after-free in AARP proxy probe The AARP proxy‐probe routine (aarp_proxy_probe_network) sends a…

CVE-2025-37838 N/A 0.0 ⚠️ KEV fixed

Apr 18, 2025

In the Linux kernel, the following vulnerability has been resolved: HSI: ssi_protocol: Fix use after free vulnerability in ssi_protocol Driver Due to Race Condition In…

CVE-2022-49026 N/A 0.0 ⚠️ KEV fixed

Oct 21, 2024

In the Linux kernel, the following vulnerability has been resolved: e100: Fix possible use after free in e100_xmit_prepare In e100_xmit_prepare(), if we can't map the…

CVE-2023-52854 N/A 0.0 ⚠️ KEV fixed

May 21, 2024

In the Linux kernel, the following vulnerability has been resolved: padata: Fix refcnt handling in padata_free_shell() In a high-load arm64 environment, the pcrypt_aead01 test in…

CVE-2024-35867 N/A 0.0 ⚠️ KEV fixed

May 19, 2024

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF in cifs_stats_proc_show() Skip sessions that are being teared down (status…

Quick Info

Patch ID: USN-7939-2

Vendor: Canonical (Ubuntu)

Severity: Unknown

CVEs Fixed: 10

Restart: Required

Vendor

Canonical (Ubuntu)

Additional Info

action:

usn id: USN-7939-2

summary: Several security issues were fixed in the Linux kernel.

usn number: 7939-2

instructions: After a standard system update you need to reboot your computer to make all the necessary changes. ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well.

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