#VU30553 Use-after-free in Linux kernel - CVE-2019-19767

Vulnerability identifier: #VU30553

Vulnerability risk: Low

CVSSv4.0: 4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2019-19767

CWE-ID: CWE-416

Exploitation vector: Local

Exploit availability: No

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

Vendor: Linux Foundation

Description

The vulnerability allows a local non-authenticated attacker to perform a denial of service (DoS) attack.

The Linux kernel before 5.4.2 mishandles ext4_expand_extra_isize, as demonstrated by use-after-free errors in __ext4_expand_extra_isize and ext4_xattr_set_entry, related to fs/ext4/inode.c and fs/ext4/super.c, aka CID-4ea99936a163.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 5.4.1

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External links
https://lists.opensuse.org/opensuse-security-announce/2020-03/msg00021.html
https://bugzilla.kernel.org/show_bug.cgi?id=205609
https://bugzilla.kernel.org/show_bug.cgi?id=205707
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.4.2
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=4ea99936a1630f51fc3a2d61a58ec4a1c4b7d55a
https://github.com/torvalds/linux/commit/4ea99936a1630f51fc3a2d61a58ec4a1c4b7d55a
https://lists.debian.org/debian-lts-announce/2020/01/msg00013.html
https://lists.debian.org/debian-lts-announce/2020/03/msg00001.html
https://security.netapp.com/advisory/ntap-20200103-0001/
https://usn.ubuntu.com/4258-1/
https://usn.ubuntu.com/4284-1/
https://usn.ubuntu.com/4287-1/
https://usn.ubuntu.com/4287-2/

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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