Description
crypto/mcryptd.c in the Linux kernel before 4.8.15 allows local users to cause a denial of service (NULL pointer dereference and system crash) by using an AF_ALG socket with an incompatible algorithm, as demonstrated by mcryptd(md5).
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 | 4.8.15-1 | — |
| Debian 13 | linux | 4.8.15-1 | — |
| Debian 12 | linux | 4.8.15-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | linux | 4.4.0-62.83 | USN-3189-1 |
| Ubuntu 16.04 LTS | linux-aws | 4.4.0-1003.12 | — |
| Ubuntu 16.04 LTS | linux-hwe | 4.8.0-39.42~16.04.1 | — |
| Ubuntu 16.04 LTS | linux-raspi2 | 4.4.0-1042.49 | USN-3189-1 |
| Ubuntu 16.04 LTS | linux-snapdragon | 4.4.0-1046.50 | USN-3189-1 |
| Ubuntu 14.04 LTS | linux-lts-xenial | 4.4.0-62.83~14.04.1 | USN-3189-2 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | kernel-rt +10 | 3.10.0-693.rt56.617.el7 | RHSA-2017:2077 |
| RHEL 7 | perf +17 | 3.10.0-693.el7 | RHSA-2017:1842 |
Advisories 4
- RHSA-2017:2077 Red Hat Security Advisory: kernel-rt security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jul 1, 2026
- RHSA-2017:1842 Red Hat Security Advisory: kernel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jul 1, 2026
- USN-3189-1 linux, linux-raspi2, linux-snapdragon vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-3189-2 linux-lts-xenial vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
References
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=48a992727d82cb7db076fa15d372178743b1f4cd
- https://github.com/torvalds/linux/commit/48a992727d82cb7db076fa15d372178743b1f4cd
- [linux-crypto] 20161202 Crash in crypto mcryptd mailing-list
- [oss-security] 20170117 CVE request -- linux kernel: crash by spawning mcrypt(alg) with incompatible algorithm mailing-list
- 95677 vdb-entry
- https://bugzilla.redhat.com/show_bug.cgi?id=1404200
- http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.8.15
- RHSA-2017:2077 vendor-advisory
- RHSA-2017:1842 vendor-advisory