Description
The __get_user_asm_ex macro in arch/x86/include/asm/uaccess.h in the Linux kernel before 4.7.5 does not initialize a certain integer variable, which allows local users to obtain sensitive information from kernel stack memory by triggering failure of a get_user_ex call.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 4.7.5-1 | — |
| Debian 13 | linux | 4.7.5-1 | — |
| Debian 12 | linux | 4.7.5-1 | — |
| Debian 7 | linux | 3.2.84-1 | DLA-772-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux-riscv +6 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv +2 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gke +4 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +4 | No fix yet | — |
| Ubuntu 16.04 LTS | linux | 4.4.0-47.68 | — |
| Ubuntu 16.04 LTS | linux-raspi2 | 4.4.0-1038.45 | USN-3161-3 |
| Ubuntu 16.04 LTS | linux-snapdragon | 4.4.0-1035.39 | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | linux | 3.13.0-132.181 | USN-3422-1 |
| Ubuntu 14.04 LTS | linux-lts-xenial | 4.4.0-47.68~14.04.1 | — |
| Ubuntu Pro 20.04 LTS | linux-azure-fde-5.15 | No fix yet | — |
Advisories 3
- USN-3422-1 linux vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DLA-772-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-3161-3 linux-raspi2 vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
References
- https://github.com/torvalds/linux/commit/1c109fabbd51863475cd12ac206bdd249aee35af
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=1c109fabbd51863475cd12ac206bdd249aee35af
- [oss-security] 20161104 Re: kernel: fix minor infoleak in get_user_ex() mailing-list
- https://bugzilla.redhat.com/show_bug.cgi?id=1391908
- 94144 vdb-entry
- http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.7.5