Improper Input Validation Affecting kernel package, versions <0:4.14.77-80.57.amzn2
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-AMZN2-KERNEL-1666547
- published27 Sept 2021
- disclosed7 Oct 2018
Introduced: 7 Oct 2018
CVE-2018-18021 (opens in a new tab)How to fix?
Upgrade Amazon-Linux:2 kernel to version 0:4.14.77-80.57.amzn2 or higher.
This issue was patched in ALAS2-2018-1100.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel package and not the kernel package as distributed by Amazon-Linux.
See How to fix? for Amazon-Linux:2 relevant fixed versions and status.
arch/arm64/kvm/guest.c in KVM in the Linux kernel before 4.18.12 on the arm64 platform mishandles the KVM_SET_ON_REG ioctl. This is exploitable by attackers who can create virtual machines. An attacker can arbitrarily redirect the hypervisor flow of control (with full register control). An attacker can also cause a denial of service (hypervisor panic) via an illegal exception return. This occurs because of insufficient restrictions on userspace access to the core register file, and because PSTATE.M validation does not prevent unintended execution modes.
References
- http://www.securityfocus.com/bid/105550
- http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-18021
- https://www.debian.org/security/2018/dsa-4313
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=2a3f93459d689d990b3ecfbe782fec89b97d3279
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d26c25a9d19b5976b319af528886f89cf455692d
- https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.12
- https://github.com/torvalds/linux/commit/2a3f93459d689d990b3ecfbe782fec89b97d3279
- https://github.com/torvalds/linux/commit/d26c25a9d19b5976b319af528886f89cf455692d
- https://www.openwall.com/lists/oss-security/2018/10/02/2
- https://access.redhat.com/errata/RHSA-2018:3656
- https://usn.ubuntu.com/3821-1/
- https://usn.ubuntu.com/3821-2/
- https://usn.ubuntu.com/3931-1/
- https://usn.ubuntu.com/3931-2/