Executive Summary

This Alert is flagged as TOP 25 Common Weakness Enumeration from CWE/SANS. For more information, you can read this.
Titlelinux security update
NameDSA-4495First vendor Publication2019-08-10
VendorDebianLast vendor Modification2019-08-10
Severity (Vendor) N/ARevision1

Security-Database Scoring CVSS v2

Cvss vector : (AV:N/AC:M/Au:N/C:C/I:C/A:C)
Cvss Base Score9.3Attack RangeNetwork
Cvss Impact Score10Attack ComplexityMedium
Cvss Expoit Score8.6AuthenticationNone Required
Calculate full CVSS 2.0 Vectors scores


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


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.


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.


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.


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).


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.


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.


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).


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.


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.


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).


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.


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).

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.

We recommend that you upgrade your linux packages.

For the detailed security status of linux please refer to its security tracker page at: https://security-tracker.debian.org/tracker/linux

Original Source

Url : http://www.debian.org/security/2019/dsa-4495

CWE : Common Weakness Enumeration

14 %CWE-416Use After Free
14 %CWE-362Race Condition
14 %CWE-200Information Exposure
7 %CWE-787Out-of-bounds Write (CWE/SANS Top 25)
7 %CWE-476NULL Pointer Dereference
7 %CWE-415Double Free
7 %CWE-399Resource Management Errors
7 %CWE-369Divide By Zero
7 %CWE-190Integer Overflow or Wraparound (CWE/SANS Top 25)
7 %CWE-125Out-of-bounds Read
7 %CWE-119Failure to Constrain Operations within the Bounds of a Memory Buffer

CPE : Common Platform Enumeration


Alert History

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2019-09-06 12:06:36
  • Multiple Updates
2019-08-11 00:18:22
  • First insertion