Linux: >> Linux Kernel >> 2.6.16.38 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
xfs: delete attr leaf freemap entries when empty
Back in commit 2a2b5932db6758 ("xfs: fix attr leaf header freemap.size
underflow"), Brian Foster observed that it's possible for a small
freemap at the end of the end of the xattr entries array to experience
a size underflow when subtracting the space consumed by an expansion of
the entries array. There are only three freemap entries, which means
that it is not a complete index of all free space in the leaf block.
This code can leave behind a zero-length freemap entry with a nonzero
base. Subsequent setxattr operations can increase the base up to the
point that it overlaps with another freemap entry. This isn't in and of
itself a problem because the code in _leaf_add that finds free space
ignores any freemap entry with zero size.
However, there's another bug in the freemap update code in _leaf_add,
which is that it fails to update a freemap entry that begins midway
through the xattr entry that was just appended to the array. That can
result in the freemap containing two entries with the same base but
different sizes (0 for the "pushed-up" entry, nonzero for the entry
that's actually tracking free space). A subsequent _leaf_add can then
allocate xattr namevalue entries on top of the entries array, leading to
data loss. But fixing that is for later.
For now, eliminate the possibility of confusion by zeroing out the base
of any freemap entry that has zero size. Because the freemap is not
intended to be a complete index of free space, a subsequent failure to
find any free space for a new xattr will trigger block compaction, which
regenerates the freemap.
It looks like this bug has been in the codebase for quite a long time.
CVSS Score
8.8
EPSS Score
0.001
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
netfilter: xt_tcpmss: check remaining length before reading optlen
Quoting reporter:
In net/netfilter/xt_tcpmss.c (lines 53-68), the TCP option parser reads
op[i+1] directly without validating the remaining option length.
If the last byte of the option field is not EOL/NOP (0/1), the code attempts
to index op[i+1]. In the case where i + 1 == optlen, this causes an
out-of-bounds read, accessing memory past the optlen boundary
(either reading beyond the stack buffer _opt or the
following payload).
CVSS Score
8.2
EPSS Score
0.001
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
net: usb: kaweth: remove TX queue manipulation in kaweth_set_rx_mode
kaweth_set_rx_mode(), the ndo_set_rx_mode callback, calls
netif_stop_queue() and netif_wake_queue(). These are TX queue flow
control functions unrelated to RX multicast configuration.
The premature netif_wake_queue() can re-enable TX while tx_urb is still
in-flight, leading to a double usb_submit_urb() on the same URB:
kaweth_start_xmit() {
netif_stop_queue();
usb_submit_urb(kaweth->tx_urb);
}
kaweth_set_rx_mode() {
netif_stop_queue();
netif_wake_queue(); // wakes TX queue before URB is done
}
kaweth_start_xmit() {
netif_stop_queue();
usb_submit_urb(kaweth->tx_urb); // URB submitted while active
}
This triggers the WARN in usb_submit_urb():
"URB submitted while active"
This is a similar class of bug fixed in rtl8150 by
- commit 958baf5eaee3 ("net: usb: Remove disruptive netif_wake_queue in rtl8150_set_multicast").
Also kaweth_set_rx_mode() is already functionally broken, the
real set_rx_mode action is performed by kaweth_async_set_rx_mode(),
which in turn is not a no-op only at ndo_open() time.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
net: usb: pegasus: enable basic endpoint checking
pegasus_probe() fills URBs with hardcoded endpoint pipes without
verifying the endpoint descriptors:
- usb_rcvbulkpipe(dev, 1) for RX data
- usb_sndbulkpipe(dev, 2) for TX data
- usb_rcvintpipe(dev, 3) for status interrupts
A malformed USB device can present these endpoints with transfer types
that differ from what the driver assumes.
Add a pegasus_usb_ep enum for endpoint numbers, replacing magic
constants throughout. Add usb_check_bulk_endpoints() and
usb_check_int_endpoints() calls before any resource allocation to
verify endpoint types before use, rejecting devices with mismatched
descriptors at probe time, and avoid triggering assertion.
Similar fix to
- commit 90b7f2961798 ("net: usb: rtl8150: enable basic endpoint checking")
- commit 9e7021d2aeae ("net: usb: catc: enable basic endpoint checking")
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
xfs: fix freemap adjustments when adding xattrs to leaf blocks
xfs/592 and xfs/794 both trip this assertion in the leaf block freemap
adjustment code after ~20 minutes of running on my test VMs:
ASSERT(ichdr->firstused >= ichdr->count * sizeof(xfs_attr_leaf_entry_t)
+ xfs_attr3_leaf_hdr_size(leaf));
Upon enabling quite a lot more debugging code, I narrowed this down to
fsstress trying to set a local extended attribute with namelen=3 and
valuelen=71. This results in an entry size of 80 bytes.
At the start of xfs_attr3_leaf_add_work, the freemap looks like this:
i 0 base 448 size 0 rhs 448 count 46
i 1 base 388 size 132 rhs 448 count 46
i 2 base 2120 size 4 rhs 448 count 46
firstused = 520
where "rhs" is the first byte past the end of the leaf entry array.
This is inconsistent -- the entries array ends at byte 448, but
freemap[1] says there's free space starting at byte 388!
By the end of the function, the freemap is in worse shape:
i 0 base 456 size 0 rhs 456 count 47
i 1 base 388 size 52 rhs 456 count 47
i 2 base 2120 size 4 rhs 456 count 47
firstused = 440
Important note: 388 is not aligned with the entries array element size
of 8 bytes.
Based on the incorrect freemap, the name area starts at byte 440, which
is below the end of the entries array! That's why the assertion
triggers and the filesystem shuts down.
How did we end up here? First, recall from the previous patch that the
freemap array in an xattr leaf block is not intended to be a
comprehensive map of all free space in the leaf block. In other words,
it's perfectly legal to have a leaf block with:
* 376 bytes in use by the entries array
* freemap[0] has [base = 376, size = 8]
* freemap[1] has [base = 388, size = 1500]
* the space between 376 and 388 is free, but the freemap stopped
tracking that some time ago
If we add one xattr, the entries array grows to 384 bytes, and
freemap[0] becomes [base = 384, size = 0]. So far, so good. But if we
add a second xattr, the entries array grows to 392 bytes, and freemap[0]
gets pushed up to [base = 392, size = 0]. This is bad, because
freemap[1] hasn't been updated, and now the entries array and the free
space claim the same space.
The fix here is to adjust all freemap entries so that none of them
collide with the entries array. Note that this fix relies on commit
2a2b5932db6758 ("xfs: fix attr leaf header freemap.size underflow") and
the previous patch that resets zero length freemap entries to have
base = 0.
CVSS Score
8.8
EPSS Score
0.001
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/pm: Fix null pointer dereference issue
If SMU is disabled, during RAS initialization,
there will be null pointer dereference issue here.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
ALSA: mixer: oss: Add card disconnect checkpoints
ALSA OSS mixer layer calls the kcontrol ops rather individually, and
pending calls might be not always caught at disconnecting the device.
For avoiding the potential UAF scenarios, add sanity checks of the
card disconnection at each entry point of OSS mixer accesses. The
rwsem is taken just before that check, hence the rest context should
be covered by that properly.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
jfs: nlink overflow in jfs_rename
If nlink is maximal for a directory (-1) and inside that directory you
perform a rename for some child directory (not moving from the parent),
then the nlink of the first directory is first incremented and later
decremented. Normally this is fine, but when nlink = -1 this causes a
wrap around to 0, and then drop_nlink issues a warning.
After applying the patch syzbot no longer issues any warnings. I also
ran some basic fs tests to look for any regressions.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ctnetlink: ensure safe access to master conntrack
Holding reference on the expectation is not sufficient, the master
conntrack object can just go away, making exp->master invalid.
To access exp->master safely:
- Grab the nf_conntrack_expect_lock, this gets serialized with
clean_from_lists() which also holds this lock when the master
conntrack goes away.
- Hold reference on master conntrack via nf_conntrack_find_get().
Not so easy since the master tuple to look up for the master conntrack
is not available in the existing problematic paths.
This patch goes for extending the nf_conntrack_expect_lock section
to address this issue for simplicity, in the cases that are described
below this is just slightly extending the lock section.
The add expectation command already holds a reference to the master
conntrack from ctnetlink_create_expect().
However, the delete expectation command needs to grab the spinlock
before looking up for the expectation. Expand the existing spinlock
section to address this to cover the expectation lookup. Note that,
the nf_ct_expect_iterate_net() calls already grabs the spinlock while
iterating over the expectation table, which is correct.
The get expectation command needs to grab the spinlock to ensure master
conntrack does not go away. This also expands the existing spinlock
section to cover the expectation lookup too. I needed to move the
netlink skb allocation out of the spinlock to keep it GFP_KERNEL.
For the expectation events, the IPEXP_DESTROY event is already delivered
under the spinlock, just move the delivery of IPEXP_NEW under the
spinlock too because the master conntrack event cache is reached through
exp->master.
While at it, add lockdep notations to help identify what codepaths need
to grab the spinlock.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
net: af_key: zero aligned sockaddr tail in PF_KEY exports
PF_KEY export paths use `pfkey_sockaddr_size()` when reserving sockaddr
payload space, so IPv6 addresses occupy 32 bytes on the wire. However,
`pfkey_sockaddr_fill()` initializes only the first 28 bytes of
`struct sockaddr_in6`, leaving the final 4 aligned bytes uninitialized.
Not every PF_KEY message is affected. The state and policy dump builders
already zero the whole message buffer before filling the sockaddr
payloads. Keep the fix to the export paths that still append aligned
sockaddr payloads with plain `skb_put()`:
- `SADB_ACQUIRE`
- `SADB_X_NAT_T_NEW_MAPPING`
- `SADB_X_MIGRATE`
Fix those paths by clearing only the aligned sockaddr tail after
`pfkey_sockaddr_fill()`.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-06