Linux: >> Linux Kernel >> 4.4.127 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
net/sched: Enforce that teql can only be used as root qdisc
Design intent of teql is that it is only supposed to be used as root qdisc.
We need to check for that constraint.
Although not important, I will describe the scenario that unearthed this
issue for the curious.
GangMin Kim <km.kim1503@gmail.com> managed to concot a scenario as follows:
ROOT qdisc 1:0 (QFQ)
├── class 1:1 (weight=15, lmax=16384) netem with delay 6.4s
└── class 1:2 (weight=1, lmax=1514) teql
GangMin sends a packet which is enqueued to 1:1 (netem).
Any invocation of dequeue by QFQ from this class will not return a packet
until after 6.4s. In the meantime, a second packet is sent and it lands on
1:2. teql's enqueue will return success and this will activate class 1:2.
Main issue is that teql only updates the parent visible qlen (sch->q.qlen)
at dequeue. Since QFQ will only call dequeue if peek succeeds (and teql's
peek always returns NULL), dequeue will never be called and thus the qlen
will remain as 0. With that in mind, when GangMin updates 1:2's lmax value,
the qfq_change_class calls qfq_deact_rm_from_agg. Since the child qdisc's
qlen was not incremented, qfq fails to deactivate the class, but still
frees its pointers from the aggregate. So when the first packet is
rescheduled after 6.4 seconds (netem's delay), a dangling pointer is
accessed causing GangMin's causing a UAF.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
can: esd_usb: esd_usb_read_bulk_callback(): fix URB memory leak
Fix similar memory leak as in commit 7352e1d5932a ("can: gs_usb:
gs_usb_receive_bulk_callback(): fix URB memory leak").
In esd_usb_open(), the URBs for USB-in transfers are allocated, added to
the dev->rx_submitted anchor and submitted. In the complete callback
esd_usb_read_bulk_callback(), the URBs are processed and resubmitted. In
esd_usb_close() the URBs are freed by calling
usb_kill_anchored_urbs(&dev->rx_submitted).
However, this does not take into account that the USB framework unanchors
the URB before the complete function is called. This means that once an
in-URB has been completed, it is no longer anchored and is ultimately not
released in esd_usb_close().
Fix the memory leak by anchoring the URB in the
esd_usb_read_bulk_callback() to the dev->rx_submitted anchor.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
ALSA: ctxfi: Fix potential OOB access in audio mixer handling
In the audio mixer handling code of ctxfi driver, the conf field is
used as a kind of loop index, and it's referred in the index callbacks
(amixer_index() and sum_index()).
As spotted recently by fuzzers, the current code causes OOB access at
those functions.
| UBSAN: array-index-out-of-bounds in /build/reproducible-path/linux-6.17.8/sound/pci/ctxfi/ctamixer.c:347:48
| index 8 is out of range for type 'unsigned char [8]'
After the analysis, the cause was found to be the lack of the proper
(re-)initialization of conj field.
This patch addresses those OOB accesses by adding the proper
initializations of the loop indices.
CVSS Score
7.1
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
crypto: authencesn - reject too-short AAD (assoclen<8) to match ESP/ESN spec
authencesn assumes an ESP/ESN-formatted AAD. When assoclen is shorter than
the minimum expected length, crypto_authenc_esn_decrypt() can advance past
the end of the destination scatterlist and trigger a NULL pointer dereference
in scatterwalk_map_and_copy(), leading to a kernel panic (DoS).
Add a minimum AAD length check to fail fast on invalid inputs.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
can: kvaser_usb: kvaser_usb_read_bulk_callback(): fix URB memory leak
Fix similar memory leak as in commit 7352e1d5932a ("can: gs_usb:
gs_usb_receive_bulk_callback(): fix URB memory leak").
In kvaser_usb_set_{,data_}bittiming() -> kvaser_usb_setup_rx_urbs(), the
URBs for USB-in transfers are allocated, added to the dev->rx_submitted
anchor and submitted. In the complete callback
kvaser_usb_read_bulk_callback(), the URBs are processed and resubmitted. In
kvaser_usb_remove_interfaces() the URBs are freed by calling
usb_kill_anchored_urbs(&dev->rx_submitted).
However, this does not take into account that the USB framework unanchors
the URB before the complete function is called. This means that once an
in-URB has been completed, it is no longer anchored and is ultimately not
released in usb_kill_anchored_urbs().
Fix the memory leak by anchoring the URB in the
kvaser_usb_read_bulk_callback() to the dev->rx_submitted anchor.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
net: usb: pegasus: fix memory leak in update_eth_regs_async()
When asynchronously writing to the device registers and if usb_submit_urb()
fail, the code fail to release allocated to this point resources.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-01-31
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: lpc18xx-dmamux: fix device leak on route allocation
Make sure to drop the reference taken when looking up the DMA mux
platform device during route allocation.
Note that holding a reference to a device does not prevent its driver
data from going away so there is no point in keeping the reference.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-01-31
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: at_hdmac: fix device leak on of_dma_xlate()
Make sure to drop the reference taken when looking up the DMA platform
device during of_dma_xlate() when releasing channel resources.
Note that commit 3832b78b3ec2 ("dmaengine: at_hdmac: add missing
put_device() call in at_dma_xlate()") fixed the leak in a couple of
error paths but the reference is still leaking on successful allocation.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-01-31
In the Linux kernel, the following vulnerability has been resolved:
btrfs: always detect conflicting inodes when logging inode refs
After rename exchanging (either with the rename exchange operation or
regular renames in multiple non-atomic steps) two inodes and at least
one of them is a directory, we can end up with a log tree that contains
only of the inodes and after a power failure that can result in an attempt
to delete the other inode when it should not because it was not deleted
before the power failure. In some case that delete attempt fails when
the target inode is a directory that contains a subvolume inside it, since
the log replay code is not prepared to deal with directory entries that
point to root items (only inode items).
1) We have directories "dir1" (inode A) and "dir2" (inode B) under the
same parent directory;
2) We have a file (inode C) under directory "dir1" (inode A);
3) We have a subvolume inside directory "dir2" (inode B);
4) All these inodes were persisted in a past transaction and we are
currently at transaction N;
5) We rename the file (inode C), so at btrfs_log_new_name() we update
inode C's last_unlink_trans to N;
6) We get a rename exchange for "dir1" (inode A) and "dir2" (inode B),
so after the exchange "dir1" is inode B and "dir2" is inode A.
During the rename exchange we call btrfs_log_new_name() for inodes
A and B, but because they are directories, we don't update their
last_unlink_trans to N;
7) An fsync against the file (inode C) is done, and because its inode
has a last_unlink_trans with a value of N we log its parent directory
(inode A) (through btrfs_log_all_parents(), called from
btrfs_log_inode_parent()).
8) So we end up with inode B not logged, which now has the old name
of inode A. At copy_inode_items_to_log(), when logging inode A, we
did not check if we had any conflicting inode to log because inode
A has a generation lower than the current transaction (created in
a past transaction);
9) After a power failure, when replaying the log tree, since we find that
inode A has a new name that conflicts with the name of inode B in the
fs tree, we attempt to delete inode B... this is wrong since that
directory was never deleted before the power failure, and because there
is a subvolume inside that directory, attempting to delete it will fail
since replay_dir_deletes() and btrfs_unlink_inode() are not prepared
to deal with dir items that point to roots instead of inodes.
When that happens the mount fails and we get a stack trace like the
following:
[87.2314] BTRFS info (device dm-0): start tree-log replay
[87.2318] BTRFS critical (device dm-0): failed to delete reference to subvol, root 5 inode 256 parent 259
[87.2332] ------------[ cut here ]------------
[87.2338] BTRFS: Transaction aborted (error -2)
[87.2346] WARNING: CPU: 1 PID: 638968 at fs/btrfs/inode.c:4345 __btrfs_unlink_inode+0x416/0x440 [btrfs]
[87.2368] Modules linked in: btrfs loop dm_thin_pool (...)
[87.2470] CPU: 1 UID: 0 PID: 638968 Comm: mount Tainted: G W 6.18.0-rc7-btrfs-next-218+ #2 PREEMPT(full)
[87.2489] Tainted: [W]=WARN
[87.2494] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[87.2514] RIP: 0010:__btrfs_unlink_inode+0x416/0x440 [btrfs]
[87.2538] Code: c0 89 04 24 (...)
[87.2568] RSP: 0018:ffffc0e741f4b9b8 EFLAGS: 00010286
[87.2574] RAX: 0000000000000000 RBX: ffff9d3ec8a6cf60 RCX: 0000000000000000
[87.2582] RDX: 0000000000000002 RSI: ffffffff84ab45a1 RDI: 00000000ffffffff
[87.2591] RBP: ffff9d3ec8a6ef20 R08: 0000000000000000 R09: ffffc0e741f4b840
[87.2599] R10: ffff9d45dc1fffa8 R11: 0000000000000003 R12: ffff9d3ee26d77e0
[87.2608] R13: ffffc0e741f4ba98 R14: ffff9d4458040800 R15: ffff9d44b6b7ca10
[87.2618] FS: 00007f7b9603a840(0000) GS:ffff9d4658982000(0000) knlGS:0000000000000000
[87.
---truncated---
CVSS Score
5.5
EPSS Score
0.0
Published
2026-01-31
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix NULL dereference on root when tracing inode eviction
When evicting an inode the first thing we do is to setup tracing for it,
which implies fetching the root's id. But in btrfs_evict_inode() the
root might be NULL, as implied in the next check that we do in
btrfs_evict_inode().
Hence, we either should set the ->root_objectid to 0 in case the root is
NULL, or we move tracing setup after checking that the root is not
NULL. Setting the rootid to 0 at least gives us the possibility to trace
this call even in the case when the root is NULL, so that's the solution
taken here.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-01-31