A flaw was found in the way the Linux kernel's networking implementation handled UDP packets with incorrect checksum values. A remote attacker could potentially use this flaw to trigger an infinite loop in the kernel, resulting in a denial of service on the system, or cause a denial of service in applications using the edge triggered epoll functionality.

It was reported [1] that iptables can allow protocols that do not have a protocol handler kernel module loaded.

Given following iptables ruleset: -P FORWARD DROP -A FORWARD -m sctp --dport 9 -j ACCEPT -A FORWARD -p tcp --dport 80 -j ACCEPT -A FORWARD -p tcp -m conntrack -m state ESTABLISHED,RELATED -j ACCEPT

One would assume that this allows SCTP on port 9 and TCP on port 80. Unfortunately, if the SCTP conntrack module is not loaded, this allows all SCTP communication to pass through, i.e. -p sctp -j ACCEPT

[1]: http://www.spinics.net/lists/netfilter-devel/msg33430.html

Last updated 24 July 2024

A flaw was found in the way reference counting was handled in the Linux kernel's VFS subsystem when unmount on symlink was performed.

On Red Hat Enterprise Linux 6 an unprivileged local user could use this flaw to cause OOM conditions leading to denial of service or, potentially, trigger use-after-free error.

On Red Hat Enterprise Linux 7 a privileged local user with CAPSYSADMIN capability (also in a container) could use this flaw to cause OOM conditions leading to denial of service or, potentially, trigger use-after-free error.

Acknowledgements:

Red Hat would like to thank Vasily Averin of Parallels for reporting this issue.

Qemu before 1.6.2 block diver for the various disk image formats used by Bochs and for the QCOW version 2 format, are vulnerable to a possible crash caused by signed data types or a logic error while creating QCOW2 snapshots, which leads to incorrectly calling updaterefcount() routine.

Qemu before 2.0 block driver for Hyper-V VHDX Images is vulnerable to infinite loops and other potential issues when calculating BAT entries, due to missing bounds checks for blocksize and logicalsectorsize variables. These are used to derive other fields like 'sectorsperblock' etc. A user able to alter the Qemu disk image could ise this flaw to crash the Qemu instance resulting in DoS.

Mozilla Firefox before 26.0 and SeaMonkey before 2.23 do not properly consider the sandbox attribute of an IFRAME element during processing of a contained OBJECT element, which allows remote attackers to bypass intended sandbox restrictions via a crafted web site.