| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
fhandle: fix UAF due to unlocked ->mnt_ns read in may_decode_fh()
may_decode_fh() accesses mount::mnt_ns without holding any locks; that
means the mount can concurrently be unmounted, and the mnt_namespace can
concurrently be freed after an RCU grace period.
This race can happens as follows, assuming that the mount point was
created by open_tree(..., OPEN_TREE_CLONE):
thread 1 thread 2 RCU
__do_sys_open_by_handle_at
do_handle_open
handle_to_path
may_decode_fh
is_mounted
[mount::mnt_ns access]
[mount::mnt_ns access]
__do_sys_close
fput_close_sync
__fput
dissolve_on_fput
umount_tree
class_namespace_excl_destructor
namespace_unlock
free_mnt_ns
mnt_ns_tree_remove
call_rcu(mnt_ns_release_rcu)
mnt_ns_release_rcu
mnt_ns_release
kfree
[mnt_namespace::user_ns access] **UAF**
Fix it by taking rcu_read_lock() around the mount::mnt_ns access, like
in __prepend_path().
Additionally, document the semantics of mount::mnt_ns, and use WRITE_ONCE()
for writers that can race with lockless readers.
This bug is unreachable unless one of the following is set:
- CONFIG_PREEMPTION
- CONFIG_RCU_STRICT_GRACE_PERIOD
because it requires an RCU grace period to happen during a syscall without
an explicit preemption.
This doesn't seem to have interesting security impact; worst-case, it could
leak the result of an integer comparison to userspace (from the level
check in cap_capable()), cause an endless loop, or crash the kernel by
dereferencing an invalid address. |
| YAML::Syck versions before 1.47 for Perl allow a use-after-free and double-free via an anchor node freed while still on the parser value stack.
In the bundled libsyck, when an anchor name is redefined or removed, syck_hdlr_add_anchor and syck_hdlr_remove_anchor free the node stored under that name with syck_free_node. That node can still be live on the parser's value stack, so syck_hdlr_add_node reaches it again and frees it a second time. On a normal build the 48-byte node chunk is freed twice and the interpreter aborts. Anchors need no special flags, so this is reached on the default Load path, and a 7-byte document that redefines an anchor triggers it.
Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor mid-parse crashes the interpreter, a denial of service. |
| YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor.
In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path.
Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory. |
| Concurrent execution using shared resource with improper synchronization ('race condition') in Windows App Store allows an unauthorized attacker to elevate privileges over a network. |
| Concurrent execution using shared resource with improper synchronization ('race condition') in Microsoft Windows App Store allows an authorized attacker to elevate privileges locally. |
| Use after free in Windows Kernel allows an authorized attacker to elevate privileges locally. |
| Use after free in Windows Remote Access Connection Manager allows an authorized attacker to elevate privileges over a network. |
| ImageMagick before 7.1.2-26 and 6.9.13-51 contains a use-after-free vulnerability that occurs when freetype initialization fails: the method does not exit and continues to use memory that was already freed. This can be triggered during image processing and may lead to a denial of service. |
| Use after free in Content Delivery Manager allows an authorized attacker to elevate privileges locally. |
| Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Clip Service allows an authorized attacker to elevate privileges locally. |
| Use after free in Windows Hyper-V allows an unauthorized attacker to elevate privileges locally. |
| Use after free in DNS Server allows an authorized attacker to execute code over a network. |
| Use after free in Windows Application Model allows an authorized attacker to elevate privileges locally. |
| Use after free in Windows Clipboard Server allows an authorized attacker to elevate privileges locally. |
| Use after free in Windows Internal Task Bar allows an authorized attacker to elevate privileges locally. |
| Concurrent execution using shared resource with improper synchronization ('race condition') in Windows App Installer allows an authorized attacker to elevate privileges locally. |
| Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Operating Systems allows an authorized attacker to elevate privileges locally. |
| Concurrent execution using shared resource with improper synchronization ('race condition') in Windows USB Driver allows an authorized attacker to elevate privileges locally. |
| Use after free in Windows Internal System User Profile allows an authorized attacker to elevate privileges locally. |
| Use after free in Windows Backup Engine allows an authorized attacker to elevate privileges locally. |
