Linux: >> Linux Kernel >> 2.6.35.7 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix out-of-bounds write in ocfs2_write_end_inline
KASAN reports a use-after-free write of 4086 bytes in
ocfs2_write_end_inline, called from ocfs2_write_end_nolock during a
copy_file_range splice fallback on a corrupted ocfs2 filesystem mounted on
a loop device. The actual bug is an out-of-bounds write past the inode
block buffer, not a true use-after-free. The write overflows into an
adjacent freed page, which KASAN reports as UAF.
The root cause is that ocfs2_try_to_write_inline_data trusts the on-disk
id_count field to determine whether a write fits in inline data. On a
corrupted filesystem, id_count can exceed the physical maximum inline data
capacity, causing writes to overflow the inode block buffer.
Call trace (crash path):
vfs_copy_file_range (fs/read_write.c:1634)
do_splice_direct
splice_direct_to_actor
iter_file_splice_write
ocfs2_file_write_iter
generic_perform_write
ocfs2_write_end
ocfs2_write_end_nolock (fs/ocfs2/aops.c:1949)
ocfs2_write_end_inline (fs/ocfs2/aops.c:1915)
memcpy_from_folio <-- KASAN: write OOB
So add id_count upper bound check in ocfs2_validate_inode_block() to
alongside the existing i_size check to fix it.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: validate inline data i_size during inode read
When reading an inode from disk, ocfs2_validate_inode_block() performs
various sanity checks but does not validate the size of inline data. If
the filesystem is corrupted, an inode's i_size can exceed the actual
inline data capacity (id_count).
This causes ocfs2_dir_foreach_blk_id() to iterate beyond the inline data
buffer, triggering a use-after-free when accessing directory entries from
freed memory.
In the syzbot report:
- i_size was 1099511627576 bytes (~1TB)
- Actual inline data capacity (id_count) is typically <256 bytes
- A garbage rec_len (54648) caused ctx->pos to jump out of bounds
- This triggered a UAF in ocfs2_check_dir_entry()
Fix by adding a validation check in ocfs2_validate_inode_block() to ensure
inodes with inline data have i_size <= id_count. This catches the
corruption early during inode read and prevents all downstream code from
operating on invalid data.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
HID: core: Mitigate potential OOB by removing bogus memset()
The memset() in hid_report_raw_event() has the good intention of
clearing out bogus data by zeroing the area from the end of the incoming
data string to the assumed end of the buffer. However, as we have
previously seen, doing so can easily result in OOB reads and writes in
the subsequent thread of execution.
The current suggestion from one of the HID maintainers is to remove the
memset() and simply return if the incoming event buffer size is not
large enough to fill the associated report.
Suggested-by Benjamin Tissoires <bentiss@kernel.org>
[bentiss: changed the return value]
CVSS Score
8.8
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
atm: lec: fix use-after-free in sock_def_readable()
A race condition exists between lec_atm_close() setting priv->lecd
to NULL and concurrent access to priv->lecd in send_to_lecd(),
lec_handle_bridge(), and lec_atm_send(). When the socket is freed
via RCU while another thread is still using it, a use-after-free
occurs in sock_def_readable() when accessing the socket's wait queue.
The root cause is that lec_atm_close() clears priv->lecd without
any synchronization, while callers dereference priv->lecd without
any protection against concurrent teardown.
Fix this by converting priv->lecd to an RCU-protected pointer:
- Mark priv->lecd as __rcu in lec.h
- Use rcu_assign_pointer() in lec_atm_close() and lecd_attach()
for safe pointer assignment
- Use rcu_access_pointer() for NULL checks that do not dereference
the pointer in lec_start_xmit(), lec_push(), send_to_lecd() and
lecd_attach()
- Use rcu_read_lock/rcu_dereference/rcu_read_unlock in send_to_lecd(),
lec_handle_bridge() and lec_atm_send() to safely access lecd
- Use rcu_assign_pointer() followed by synchronize_rcu() in
lec_atm_close() to ensure all readers have completed before
proceeding. This is safe since lec_atm_close() is called from
vcc_release() which holds lock_sock(), a sleeping lock.
- Remove the manual sk_receive_queue drain from lec_atm_close()
since vcc_destroy_socket() already drains it after lec_atm_close()
returns.
v2: Switch from spinlock + sock_hold/put approach to RCU to properly
fix the race. The v1 spinlock approach had two issues pointed out
by Eric Dumazet:
1. priv->lecd was still accessed directly after releasing the
lock instead of using a local copy.
2. The spinlock did not prevent packets being queued after
lec_atm_close() drains sk_receive_queue since timer and
workqueue paths bypass netif_stop_queue().
Note: Syzbot patch testing was attempted but the test VM terminated
unexpectedly with "Connection to localhost closed by remote host",
likely due to a QEMU AHCI emulation issue unrelated to this fix.
Compile testing with "make W=1 net/atm/lec.o" passes cleanly.
CVSS Score
7.0
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
xfs: close crash window in attr dabtree inactivation
When inactivating an inode with node-format extended attributes,
xfs_attr3_node_inactive() invalidates all child leaf/node blocks via
xfs_trans_binval(), but intentionally does not remove the corresponding
entries from their parent node blocks. The implicit assumption is that
xfs_attr_inactive() will truncate the entire attr fork to zero extents
afterwards, so log recovery will never reach the root node and follow
those stale pointers.
However, if a log shutdown occurs after the leaf/node block cancellations
commit but before the attr bmap truncation commits, this assumption
breaks. Recovery replays the attr bmap intact (the inode still has
attr fork extents), but suppresses replay of all cancelled leaf/node
blocks, maybe leaving them as stale data on disk. On the next mount,
xlog_recover_process_iunlinks() retries inactivation and attempts to
read the root node via the attr bmap. If the root node was not replayed,
reading the unreplayed root block triggers a metadata verification
failure immediately; if it was replayed, following its child pointers
to unreplayed child blocks triggers the same failure:
XFS (pmem0): Metadata corruption detected at
xfs_da3_node_read_verify+0x53/0x220, xfs_da3_node block 0x78
XFS (pmem0): Unmount and run xfs_repair
XFS (pmem0): First 128 bytes of corrupted metadata buffer:
00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
XFS (pmem0): metadata I/O error in "xfs_da_read_buf+0x104/0x190" at daddr 0x78 len 8 error 117
Fix this in two places:
In xfs_attr3_node_inactive(), after calling xfs_trans_binval() on a
child block, immediately remove the entry that references it from the
parent node in the same transaction. This eliminates the window where
the parent holds a pointer to a cancelled block. Once all children are
removed, the now-empty root node is converted to a leaf block within the
same transaction. This node-to-leaf conversion is necessary for crash
safety. If the system shutdown after the empty node is written to the
log but before the second-phase bmap truncation commits, log recovery
will attempt to verify the root block on disk. xfs_da3_node_verify()
does not permit a node block with count == 0; such a block will fail
verification and trigger a metadata corruption shutdown. on the other
hand, leaf blocks are allowed to have this transient state.
In xfs_attr_inactive(), split the attr fork truncation into two explicit
phases. First, truncate all extents beyond the root block (the child
extents whose parent references have already been removed above).
Second, invalidate the root block and truncate the attr bmap to zero in
a single transaction. The two operations in the second phase must be
atomic: as long as the attr bmap has any non-zero length, recovery can
follow it to the root block, so the root block invalidation must commit
together with the bmap-to-zero truncation.
CVSS Score
4.7
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
net: ipv6: ndisc: fix ndisc_ra_useropt to initialize nduseropt_padX fields to zero to prevent an info-leak
When processing Router Advertisements with user options the kernel
builds an RTM_NEWNDUSEROPT netlink message. The nduseroptmsg struct
has three padding fields that are never zeroed and can leak kernel data
The fix is simple, just zeroes the padding fields.
CVSS Score
7.1
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
btrfs: reject root items with drop_progress and zero drop_level
[BUG]
When recovering relocation at mount time, merge_reloc_root() and
btrfs_drop_snapshot() both use BUG_ON(level == 0) to guard against
an impossible state: a non-zero drop_progress combined with a zero
drop_level in a root_item, which can be triggered:
------------[ cut here ]------------
kernel BUG at fs/btrfs/relocation.c:1545!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 283 ... Tainted: 6.18.0+ #16 PREEMPT(voluntary)
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU Ubuntu 24.04 PC v2, BIOS 1.16.3-debian-1.16.3-2
RIP: 0010:merge_reloc_root+0x1266/0x1650 fs/btrfs/relocation.c:1545
Code: ffff0000 00004589 d7e9acfa ffffe8a1 79bafebe 02000000
Call Trace:
merge_reloc_roots+0x295/0x890 fs/btrfs/relocation.c:1861
btrfs_recover_relocation+0xd6e/0x11d0 fs/btrfs/relocation.c:4195
btrfs_start_pre_rw_mount+0xa4d/0x1810 fs/btrfs/disk-io.c:3130
open_ctree+0x5824/0x5fe0 fs/btrfs/disk-io.c:3640
btrfs_fill_super fs/btrfs/super.c:987 [inline]
btrfs_get_tree_super fs/btrfs/super.c:1951 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2094 [inline]
btrfs_get_tree+0x111c/0x2190 fs/btrfs/super.c:2128
vfs_get_tree+0x9a/0x370 fs/super.c:1758
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3642 [inline]
do_new_mount fs/namespace.c:3718 [inline]
path_mount+0x5b8/0x1ea0 fs/namespace.c:4028
do_mount fs/namespace.c:4041 [inline]
__do_sys_mount fs/namespace.c:4229 [inline]
__se_sys_mount fs/namespace.c:4206 [inline]
__x64_sys_mount+0x282/0x320 fs/namespace.c:4206
...
RIP: 0033:0x7f969c9a8fde
Code: 0f1f4000 48c7c2b0 fffffff7 d8648902 b8ffffff ffc3660f
---[ end trace 0000000000000000 ]---
The bug is reproducible on 7.0.0-rc2-next-20260310 with our dynamic
metadata fuzzing tool that corrupts btrfs metadata at runtime.
[CAUSE]
A non-zero drop_progress.objectid means an interrupted
btrfs_drop_snapshot() left a resume point on disk, and in that case
drop_level must be greater than 0 because the checkpoint is only
saved at internal node levels.
Although this invariant is enforced when the kernel writes the root
item, it is not validated when the root item is read back from disk.
That allows on-disk corruption to provide an invalid state with
drop_progress.objectid != 0 and drop_level == 0.
When relocation recovery later processes such a root item,
merge_reloc_root() reads drop_level and hits BUG_ON(level == 0). The
same invalid metadata can also trigger the corresponding BUG_ON() in
btrfs_drop_snapshot().
[FIX]
Fix this by validating the root_item invariant in tree-checker when
reading root items from disk: if drop_progress.objectid is non-zero,
drop_level must also be non-zero. Reject such malformed metadata with
-EUCLEAN before it reaches merge_reloc_root() or btrfs_drop_snapshot()
and triggers the BUG_ON.
After the fix, the same corruption is correctly rejected by tree-checker
and the BUG_ON is no longer triggered.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
ip6_tunnel: clear skb2->cb[] in ip4ip6_err()
Oskar Kjos reported the following problem.
ip4ip6_err() calls icmp_send() on a cloned skb whose cb[] was written
by the IPv6 receive path as struct inet6_skb_parm. icmp_send() passes
IPCB(skb2) to __ip_options_echo(), which interprets that cb[] region
as struct inet_skb_parm (IPv4). The layouts differ: inet6_skb_parm.nhoff
at offset 14 overlaps inet_skb_parm.opt.rr, producing a non-zero rr
value. __ip_options_echo() then reads optlen from attacker-controlled
packet data at sptr[rr+1] and copies that many bytes into dopt->__data,
a fixed 40-byte stack buffer (IP_OPTIONS_DATA_FIXED_SIZE).
To fix this we clear skb2->cb[], as suggested by Oskar Kjos.
Also add minimal IPv4 header validation (version == 4, ihl >= 5).
CVSS Score
9.8
EPSS Score
0.001
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
net/x25: Fix potential double free of skb
When alloc_skb fails in x25_queue_rx_frame it calls kfree_skb(skb) at
line 48 and returns 1 (error).
This error propagates back through the call chain:
x25_queue_rx_frame returns 1
|
v
x25_state3_machine receives the return value 1 and takes the else
branch at line 278, setting queued=0 and returning 0
|
v
x25_process_rx_frame returns queued=0
|
v
x25_backlog_rcv at line 452 sees queued=0 and calls kfree_skb(skb)
again
This would free the same skb twice. Looking at x25_backlog_rcv:
net/x25/x25_in.c:x25_backlog_rcv() {
...
queued = x25_process_rx_frame(sk, skb);
...
if (!queued)
kfree_skb(skb);
}
CVSS Score
9.8
EPSS Score
0.001
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
ALSA: ctxfi: Check the error for index mapping
The ctxfi driver blindly assumed a proper value returned from
daio_device_index(), but it's not always true. Add a proper error
check to deal with the error from the function.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-01