Debian DSA-4495-1 : linux - security update

high Nessus Plugin ID 127491


The remote Debian host is missing a security-related update.


Several vulnerabilities have been discovered in the Linux kernel that may lead to a privilege escalation, denial of service or information leaks.

- CVE-2018-20836 chenxiang reported a race condition in libsas, the kernel subsystem supporting Serial Attached SCSI (SAS) devices, which could lead to a use-after-free. It is not clear how this might be exploited.

- CVE-2019-1125 It was discovered that most x86 processors could speculatively skip a conditional SWAPGS instruction used when entering the kernel from user mode, and/or could speculatively execute it when it should be skipped. This is a subtype of Spectre variant 1, which could allow local users to obtain sensitive information from the kernel or other processes. It has been mitigated by using memory barriers to limit speculative execution.
Systems using an i386 kernel are not affected as the kernel does not use SWAPGS.

- CVE-2019-1999 A race condition was discovered in the Android binder driver, which could lead to a use-after-free. If this driver is loaded, a local user might be able to use this for denial-of-service (memory corruption) or for privilege escalation.

- CVE-2019-10207 The syzkaller tool found a potential null dereference in various drivers for UART-attached Bluetooth adapters. A local user with access to a pty device or other suitable tty device could use this for denial-of-service (BUG/oops).

- CVE-2019-10638 Amit Klein and Benny Pinkas discovered that the generation of IP packet IDs used a weak hash function, 'jhash'. This could enable tracking individual computers as they communicate with different remote servers and from different networks. The 'siphash' function is now used instead.

- CVE-2019-12817 It was discovered that on the PowerPC (ppc64el) architecture, the hash page table (HPT) code did not correctly handle fork() in a process with memory mapped at addresses above 512 TiB. This could lead to a use-after-free in the kernel, or unintended sharing of memory between user processes. A local user could use this for privilege escalation. Systems using the radix MMU, or a custom kernel with a 4 KiB page size, are not affected.

- CVE-2019-12984 It was discovered that the NFC protocol implementation did not properly validate a netlink control message, potentially leading to a NULL pointer dereference. A local user on a system with an NFC interface could use this for denial-of-service (BUG/oops).

- CVE-2019-13233 Jann Horn discovered a race condition on the x86 architecture, in use of the LDT. This could lead to a use-after-free. A local user could possibly use this for denial-of-service.

- CVE-2019-13631 It was discovered that the gtco driver for USB input tablets could overrun a stack buffer with constant data while parsing the device's descriptor. A physically present user with a specially constructed USB device could use this to cause a denial-of-service (BUG/oops), or possibly for privilege escalation.

- CVE-2019-13648 Praveen Pandey reported that on PowerPC (ppc64el) systems without Transactional Memory (TM), the kernel would still attempt to restore TM state passed to the sigreturn() system call. A local user could use this for denial-of-service (oops).

- CVE-2019-14283 The syzkaller tool found a missing bounds check in the floppy disk driver. A local user with access to a floppy disk device, with a disk present, could use this to read kernel memory beyond the I/O buffer, possibly obtaining sensitive information.

- CVE-2019-14284 The syzkaller tool found a potential division-by-zero in the floppy disk driver. A local user with access to a floppy disk device could use this for denial-of-service (oops).


Upgrade the linux packages.

For the stable distribution (buster), these problems have been fixed in version 4.19.37-5+deb10u2.

For the oldstable distribution (stretch), these problems will be fixed soon.

See Also

Plugin Details

Severity: High

ID: 127491

File Name: debian_DSA-4495.nasl

Version: 1.2

Type: local

Agent: unix

Published: 8/12/2019

Updated: 9/24/2019

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Nessus Agent

Risk Information


Risk Factor: High

Score: 7.4


Risk Factor: High

Base Score: 9.3

Temporal Score: 7.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C


Risk Factor: High

Base Score: 8.1

Temporal Score: 7.3

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:linux, cpe:/o:debian:debian_linux:10.0

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 8/10/2019

Vulnerability Publication Date: 2/28/2019

Reference Information

CVE: CVE-2018-20836, CVE-2019-10207, CVE-2019-10638, CVE-2019-1125, CVE-2019-12817, CVE-2019-12984, CVE-2019-13233, CVE-2019-13631, CVE-2019-13648, CVE-2019-14283, CVE-2019-14284, CVE-2019-1999

DSA: 4495