Amazon Linux 2 : kernel, --advisory ALAS2KERNEL-5.15-2026-111 (ALASKERNEL-5.15-2026-111)

high Nessus Plugin ID 330281

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Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of kernel installed on the remote host is prior to 5.15.211-149.249. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2KERNEL-5.15-2026-111 advisory.

In the Linux kernel, the following vulnerability has been resolved:

ext4: replace BUG_ON with proper error handling in ext4_read_inline_folio (CVE-2026-31451)

In the Linux kernel, the following vulnerability has been resolved:

net/sched: fix pedit partial COW leading to page cache corruption (CVE-2026-46331)

In the Linux kernel, the following vulnerability has been resolved:

ip6_vti: set netns_immutable on the fallback device. (CVE-2026-52909)

In the Linux kernel, the following vulnerability has been resolved:

af_unix: Reject SIOCATMARK on non-stream sockets (CVE-2026-52928)

In the Linux kernel, the following vulnerability has been resolved:

fuse: limit FUSE_NOTIFY_RETRIEVE to uptodate folios (CVE-2026-53167)

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86: Fix shadow paging use-after-free due to unexpected role (CVE-2026-53359)

In the Linux kernel, the following vulnerability has been resolved:

virtiofs: fix UAF on submount umount

iput() called from fuse_release_end() can Oops if the super block hasalready been destroyed. Normally this is prevented by waiting fornum_waiting to go down to zero before commencing with super block shutdown.

This only works, however, for the last submount instance, as the waitcounter is per connection, not per superblock.

Revert to using synchronous release requests for the auto_submounts case,which is virtiofs only at this time. (CVE-2026-53381)

In the Linux kernel, the following vulnerability has been resolved:

vc_screen: fix null-ptr-deref in vcs_notifier() during concurrent vcs_write

A KASAN null-ptr-deref was observed in vcs_notifier():

BUG: KASAN: null-ptr-deref in vcs_notifier+0x98/0x130Read of size 2 at addr qmp_cmd_name:
qmp_capabilities, arguments: {}

The issue is a race condition in vcs_write(). When the console_lock istemporarily dropped (to copy data from userspace), the vc_data pointerobtained from vcs_vc() may become stale. After re-acquiring the lock,vcs_vc() is called again to re-validate the pointer. If the vc has beendeallocated in the meantime, vcs_vc() returns NULL, and the while loopbreaks (with written > 0). However, after the loop, vcs_scr_updated(vc)is still called with the now-NULL vc pointer, leading to a null pointerdereference in the notifier chain (vcs_notifier dereferences param->vc).

Fix this by adding a NULL check for vc before calling vcs_scr_updated(). (CVE-2026-53385)

In the Linux kernel, the following vulnerability has been resolved:

fuse: re-lock request before replacing page cache folio

fuse_try_move_folio() unlocks the request on entry but does notre-lock it on the success path. This means fuse_chan_abort() can end therequest and free the fuse_io_args (eg fuse_readpages_end()) while thesubsequent copy chain logic after fuse_try_move_folio() accesses thefuse_io_args, leading to use-after- free issues.

Fix this by calling lock_request() before replace_page_cache_folio().This ensures the request is locked on the success path which willprevent the fuse_io_args from being freed while the later copying logicruns, and also ensures that the ap->folios[i]->mapping is never nullsince ap->folios[i] will always point to the newfolio afterreplace_page_cache_folio(). (CVE-2026-53388)

In the Linux kernel, the following vulnerability has been resolved:

NFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr (CVE-2026-53391)

In the Linux kernel, the following vulnerability has been resolved:

nfsd: fix posix_acl leak on SETACL decode failure (CVE-2026-53397)

In the Linux kernel, the following vulnerability has been resolved:

NFSD: Fix SECINFO_NO_NAME decode error cleanup (CVE-2026-53398)

In the Linux kernel, the following vulnerability has been resolved:

fbdev: Fix fb_new_modelist to prevent null-ptr-deref in fb_videomode_to_var

info->var, a framebuffer's current mode, is expected to have a matchingentry in info->modelist.
var_to_display() relies on this and treats afailed fb_match_mode() as This should not happen.
fb_set_var() keeps ittrue by adding the mode to the list on every change, anddo_register_framebuffer() does the same at registration.

store_modes() replaces the modelist from userspace. fb_new_modelist()validates the new modes but does not check that info->var still has amatch. It relies on fbcon_new_modelist() to re-point consoles, but thatonly handles consoles mapped to the framebuffer. With fbcon unbound thereare none, so info->var is left describing a mode that is no longer in thelist.

A later console takeover runs var_to_display(), where fb_match_mode()returns NULL and leaves fb_display[i].mode NULL. fbcon_switch() passes itto display_to_var(), and fb_videomode_to_var() dereferences the NULL mode.

Keep the current mode in the list in fb_new_modelist(), the same wayfb_set_var() does. (CVE-2026-53403)

In the Linux kernel, the following vulnerability has been resolved:

KVM: SVM: Fix page overflow in sev_dbg_crypt() for ENCRYPT path (CVE-2026-63794)

In the Linux kernel, the following vulnerability has been resolved:

pNFS: Fix use-after-free in pnfs_update_layout() (CVE-2026-63800)

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86/mmu: Ensure hugepage is in by slot before checking max mapping level (CVE-2026-63807)

In the Linux kernel, the following vulnerability has been resolved:

exfat: fix potential use-after-free in exfat_find_dir_entry() (CVE-2026-63808)

In the Linux kernel, the following vulnerability has been resolved:

bpf: use kvfree() for replaced sysctl write buffer (CVE-2026-63809)

In the Linux kernel, the following vulnerability has been resolved:

keys: Pin request_key_auth payload in instantiate paths (CVE-2026-63823)

In the Linux kernel, the following vulnerability has been resolved:

KEYS: fix overflow in keyctl_pkey_params_get_2() (CVE-2026-63824)

In the Linux kernel, the following vulnerability has been resolved:

ntfs3: reject direct userspace writes to reserved $LX* xattrs

NTFS3 uses $LXUID, $LXGID, $LXMOD and $LXDEV as internal WSLpermission metadata and reloads them into i_uid, i_gid and i_modefrom ntfs_get_wsl_perm().

Because the empty-prefix xattr handler also lets file owners callsetxattr() on these names directly, an unprivileged writer on awritable ntfs3 mount can plant root ownership and S_ISUID on their ownfile and gain euid 0 after inode reload.

Reject direct userspace writes to the reserved $LX* names. Internalntfs3 metadata updates are unchanged because ntfs_save_wsl_perm()writes them via ntfs_set_ea() directly.

[[email protected]: added an additional check for non privileged users] (CVE-2026-63833)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Run 'yum update kernel' or or 'yum update --advisory ALAS2KERNEL-5.15-2026-111' to update your system.

Plugin Details

Severity: High

ID: 330281

File Name: al2_ALASKERNEL-5_15-2026-111.nasl

Version: 1.4

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 7/28/2026

Updated: 8/12/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Critical

Score: 9

Percentile: 99.75

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5.3

Vector: CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C

CVSS Score Source: CVE-2026-63794

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:bpftool-debuginfo, p-cpe:/a:amazon:linux:bpftool, p-cpe:/a:amazon:linux:kernel-debuginfo-common-aarch64, p-cpe:/a:amazon:linux:kernel-debuginfo-common-x86_64, p-cpe:/a:amazon:linux:kernel-debuginfo, p-cpe:/a:amazon:linux:kernel-devel, p-cpe:/a:amazon:linux:kernel-headers, p-cpe:/a:amazon:linux:kernel-livepatch-5.15.211-149.249, p-cpe:/a:amazon:linux:kernel-tools-debuginfo, p-cpe:/a:amazon:linux:kernel-tools-devel, p-cpe:/a:amazon:linux:kernel-tools, p-cpe:/a:amazon:linux:kernel, p-cpe:/a:amazon:linux:perf-debuginfo, p-cpe:/a:amazon:linux:perf, p-cpe:/a:amazon:linux:python-perf-debuginfo, p-cpe:/a:amazon:linux:python-perf

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 7/27/2026

Vulnerability Publication Date: 4/22/2026

Reference Information

CVE: CVE-2026-31451, CVE-2026-46331, CVE-2026-52909, CVE-2026-52928, CVE-2026-53167, CVE-2026-53359, CVE-2026-53381, CVE-2026-53385, CVE-2026-53388, CVE-2026-53391, CVE-2026-53397, CVE-2026-53398, CVE-2026-53403, CVE-2026-63794, CVE-2026-63800, CVE-2026-63807, CVE-2026-63808, CVE-2026-63809, CVE-2026-63823, CVE-2026-63824, CVE-2026-63833

Detections

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