Linux Kernel up to 6.12.74/6.18.13/6.19.3 AppArmor match.c get_unaligned_xx stack-based overflow

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.12.74/6.18.13/6.19.3. It has been declared as critical. Impacted is the function get_unaligned_xx of the file security/apparmor/match.c of the component AppArmor. Executing a manipulation can lead to stack-based overflow. The identification of this vulnerability is CVE-2026-46254. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.12.74/6.18.13/6.19.3. This vulnerability affects the function get_unaligned_xx of the file security/apparmor/match.c of the component AppArmor. The manipulation with an unknown input leads to a stack-based overflow vulnerability. The CWE definition for the vulnerability is CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: AppArmor: Allow apparmor to handle unaligned dfa tables The dfa tables can originate from kernel or userspace and 8-byte alignment isn't always guaranteed and as such may trigger unaligned memory accesses on various architectures. Resulting in the following [   73.901376] WARNING: CPU: 0 PID: 341 at security/apparmor/match.c:316 aa_dfa_unpack+0x6cc/0x720 [   74.015867] Modules linked in: binfmt_misc evdev flash sg drm drm_panel_orientation_quirks backlight i2c_core configfs nfnetlink autofs4 ext4 crc16 mbcache jbd2 hid_generic usbhid sr_mod hid cdrom sd_mod ata_generic ohci_pci ehci_pci ehci_hcd ohci_hcd pata_ali libata sym53c8xx scsi_transport_spi tg3 scsi_mod usbcore libphy scsi_common mdio_bus usb_common [   74.428977] CPU: 0 UID: 0 PID: 341 Comm: apparmor_parser Not tainted 6.18.0-rc6+ #9 NONE [   74.536543] Call Trace: [   74.568561] [] dump_stack+0x8/0x18 [   74.633757] [] __warn+0xd8/0x100 [   74.696664] [] warn_slowpath_fmt+0x34/0x74 [   74.771006] [] aa_dfa_unpack+0x6cc/0x720 [   74.843062] [] unpack_pdb+0xbc/0x7e0 [   74.910545] [] unpack_profile+0xbe0/0x1300 [   74.984888] [] aa_unpack+0xe0/0x6a0 [   75.051226] [] aa_replace_profiles+0x64/0x1160 [   75.130144] [] policy_update+0xf0/0x280 [   75.201057] [] profile_replace+0xa8/0x100 [   75.274258] [] vfs_write+0x90/0x420 [   75.340594] [] ksys_write+0x4c/0xe0 [   75.406932] [] sys_write+0x14/0x40 [   75.472126] [] linux_sparc_syscall+0x34/0x44 [   75.548802] ---[ end trace 0000000000000000 ]--- [   75.609503] dfa blob stream 0xfff0000008926b96 not aligned. [   75.682695] Kernel unaligned access at TPC[8db2a8] aa_dfa_unpack+0x6e8/0x720 Work around it by using the get_unaligned_xx() helpers.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-46254 since 05/13/2026. The exploitation appears to be easy. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 06/03/2026).

Upgrading to version 6.12.75, 6.18.14 or 6.19.4 eliminates this vulnerability. Applying the patch ec737e7fdf2f0ba7b203d4ec72cc915978b10e7e/23f112bd6144e815153462e12d313ac3e7027168/cded636008bde2b397a7cf63b8299d7c303aaf6a/64802f731214a51dfe3c6c27636b3ddafd003eb0 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.12.23
• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.12.40
• 6.12.41
• 6.12.42
• 6.12.43
• 6.12.44
• 6.12.45
• 6.12.46
• 6.12.47
• 6.12.48
• 6.12.49
• 6.12.50
• 6.12.51
• 6.12.52
• 6.12.53
• 6.12.54
• 6.12.55
• 6.12.56
• 6.12.57
• 6.12.58
• 6.12.59
• 6.12.60
• 6.12.61
• 6.12.62
• 6.12.63
• 6.12.64
• 6.12.65
• 6.12.66
• 6.12.67
• 6.12.68
• 6.12.69
• 6.12.70
• 6.12.71
• 6.12.72
• 6.12.73
• 6.12.74
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.19.0
• 6.19.1
• 6.19.2
• 6.19.3

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Entryinfo

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