#VU12265 Use-after-free error in Linux kernel - CVE-2017-15126

Vulnerability identifier: #VU12265

Vulnerability risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2017-15126

CWE-ID: CWE-416

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description
The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The weakness exists in fs/userfaultfd.c due to the handling of fork failure when dealing with event messages. Failure to fork correctly can lead to a situation where a fork event will be removed from an already freed list of events with userfaultfd_ctx_put(). A remote attacker can trigger use-after-free error and execute arbitrary code.

Successful exploitation of the vulnerability may result in system compromise.

Mitigation
Update to version 4.13.6.

Vulnerable software versions

Linux kernel: 4.13 - 4.13.5

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External links
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=384632e67e0829deb8015e...

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.