Linux: >> Linux Kernel >> 4.9.30 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
agp/amd64: Fix broken error propagation in agp_amd64_probe()
A NULL pointer dereference was observed in the AMD64 AGP driver when
running in a virtualized environment (e.g. qemu/kvm) without a physical
AMD northbridge. The crash occurs in amd64_fetch_size() when attempting
to dereference the pointer returned by node_to_amd_nb(0).
The root cause of this crash is broken error propagation in
agp_amd64_probe(): When no AMD northbridges are found, cache_nbs()
correctly returns -ENODEV. However, the probe function erroneously
checks the return value against exactly -1, rather than < 0.
As a result, the hardware absence error is masked, allowing the driver
to improperly proceed with initialization. It eventually calls
agp_add_bridge(), which invokes amd64_fetch_size(). Since the hardware
does not exist, node_to_amd_nb(0) returns NULL, leading to a General
Protection Fault (GPF) when accessing its ->misc member.
Fix the issue by correcting the error check in agp_amd64_probe() to
abort properly when cache_nbs() returns any negative error code. This
prevents the driver from erroneously proceeding without hardware, thereby
avoiding the subsequent NULL pointer dereference at its source.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-06-29
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: reject zero bd_oblocknr in nilfs_ioctl_mark_blocks_dirty()
nilfs_ioctl_mark_blocks_dirty() uses bd_oblocknr to detect dead blocks
by comparing it with the current block number bd_blocknr. If they differ,
the block is considered dead and skipped.
However, bd_oblocknr should never be 0 since block 0 typically stores the
primary superblock and is never a valid GC target block. A corrupted ioctl
request with bd_oblocknr set to 0 causes the comparison to incorrectly
match when the lookup returns -ENOENT and sets bd_blocknr to 0, bypassing
the dead block check and calling nilfs_bmap_mark() on a non-existent
block. This causes nilfs_btree_do_lookup() to return -ENOENT, triggering
the WARN_ON(ret == -ENOENT).
Fix this by rejecting ioctl requests with bd_oblocknr set to 0 at the
beginning of each iteration.
[ryusuke: slightly modified the commit message and comments for accuracy]
CVSS Score
5.5
EPSS Score
0.002
Published
2026-06-26
In the Linux kernel, the following vulnerability has been resolved:
ocfs2/dlm: fix off-by-one in dlm_match_regions() region comparison
The local-vs-remote region comparison loop uses '<=' instead of '<',
causing it to read one entry past the valid range of qr_regions. The
other loops in the same function correctly use '<'.
Fix the loop condition to use '<' for consistency and correctness.
CVSS Score
9.8
EPSS Score
0.004
Published
2026-06-26
In the Linux kernel, the following vulnerability has been resolved:
scsi: sg: Resolve soft lockup issue when opening /dev/sgX
The parameter def_reserved_size defines the default buffer size reserved
for each Sg_fd and should be restricted to a range between 0 and 1,048,576
(see https://tldp.org/HOWTO/SCSI-Generic-HOWTO/proc.html). Although the
function sg_proc_write_dressz enforces this limit, it is possible to bypass
it by directly modifying the module parameter as shown below, which then
causes a soft lockup:
echo -1 > /sys/module/sg/parameters/def_reserved_size
exec 4<> /dev/sg0
watchdog: BUG: soft lockup - CPU#5 stuck for 26 seconds! [bash:537]
Modules loaded:
CPU: 5 UID: 0 PID: 537 Command: bash, kernel version 6.19.0-rc3+ #134,
PREEMPT disabled
Hardware: QEMU Standard PC (i440FX + PIIX, 1996), BIOS version
1.16.1-2.fc37 dated 04/01/2014
...
Call Trace:
sg_build_reserve+0x5c/0xa0
sg_add_sfp+0x168/0x270
sg_open+0x16e/0x340
chrdev_open+0xbe/0x230
do_dentry_open+0x175/0x480
vfs_open+0x34/0xf0
do_open+0x265/0x3d0
path_openat+0x110/0x290
do_filp_open+0xc3/0x170
do_sys_openat2+0x71/0xe0
__x64_sys_openat+0x6d/0xa0
do_syscall_64+0x62/0x310
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The fix is to use module_param_cb to validate and reject invalid values
assigned to def_reserved_size.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-06-26
In the Linux kernel, the following vulnerability has been resolved:
tty: hvc_iucv: fix off-by-one in number of supported devices
MAX_HVC_IUCV_LINES == HVC_ALLOC_TTY_ADAPTERS == 8.
This is the number of entries in:
static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
Sometimes hvc_iucv_table[] is limited by:
(a) if (num > hvc_iucv_devices) // for error detection
or
(b) for (i = 0; i < hvc_iucv_devices; i++) // in 2 places
(so these 2 don't agree; second one appears to be correct to me.)
hvc_iucv_devices can be 0..8. This is a counter.
(c) if (hvc_iucv_devices > MAX_HVC_IUCV_LINES)
If hvc_iucv_devices == 8, (a) allows the code to access hvc_iucv_table[8].
Oops.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-06-26
In the Linux kernel, the following vulnerability has been resolved:
sctp: validate embedded INIT chunk and address list lengths in cookie
sctp_unpack_cookie() only checked that the embedded INIT chunk length
did not exceed the remaining cookie payload, but did not ensure that the
INIT chunk is large enough to contain a complete INIT header.
A malformed COOKIE_ECHO can therefore carry a truncated INIT chunk whose
length field is smaller than sizeof(struct sctp_init_chunk). Later,
sctp_process_init() accesses INIT parameters unconditionally, which may
lead to out-of-bounds reads.
In addition, raw_addr_list_len is not fully validated against the
remaining cookie payload. When cookie authentication is disabled, an
attacker can supply an oversized raw_addr_list_len and cause
sctp_raw_to_bind_addrs() to read beyond the end of the cookie. The
address parser also lacks sufficient bounds checks for parameter headers
and lengths, allowing malformed address parameters to trigger
out-of-bounds reads.
Fix this by:
- requiring the embedded INIT chunk length to be at least sizeof(struct
sctp_init_chunk);
- validating that the INIT chunk and raw address list together fit
within the cookie payload;
- verifying sufficient data exists for each address parameter header and
payload before parsing it.
Note that sctp_verify_init() must be called after sctp_unpack_cookie()
and before sctp_process_init() when cookie authentication is disabled.
This will be addressed in a separate patch.
CVSS Score
9.1
EPSS Score
0.005
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
sctp: fix uninit-value in __sctp_rcv_asconf_lookup()
__sctp_rcv_asconf_lookup() in net/sctp/input.c only checks that the ASCONF
chunk can hold the ADDIP header and a parameter header, then calls
af->from_addr_param(), which reads the full address (16 bytes for IPv6)
trusting the parameter's declared length.
An unauthenticated peer can send a truncated trailing ASCONF chunk that
declares an IPv6 address parameter but stops after the 4-byte parameter
header; reached from the no-association lookup path, from_addr_param() then
reads uninitialized bytes past the parameter.
Impact: an unauthenticated SCTP peer makes the receive path read up to 16
bytes of uninitialized memory past a truncated ASCONF address parameter.
The sibling __sctp_rcv_init_lookup() bounds parameters with
sctp_walk_params(); this path open-codes the fetch and omits the bound.
Verify the whole address parameter lies within the chunk before
from_addr_param() reads it, the same class of fix as commit 51e5ad549c43
("net: sctp: fix KMSAN uninit-value in sctp_inq_pop").
CVSS Score
9.1
EPSS Score
0.005
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: fix possible kfree_skb of ERR_PTR
After the patch in the "Fixes" tag, the allocation of the "reply" skb
can happen either before or after locking the ovs_mutex.
However, error cleanups still follow the classical reversed order,
assuming "reply" is allocated before locking: it is freed after unlocking.
If "reply" allocation happens after locking the mutex and it fails,
"reply" is left with an ERR_PTR, and execution jumps to the correspondent
cleanup stage which will try to free an invalid pointer.
Fix this by setting the pointer to NULL after having saved its error
value.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
ipv6: sit: reload inner IPv6 header after GSO offloads
ipip6_tunnel_xmit() caches the inner IPv6 header pointer at function
entry and continues using it after iptunnel_handle_offloads().
For GSO skbs, iptunnel_handle_offloads() calls skb_header_unclone().
When the skb header is cloned, skb_header_unclone() can call
pskb_expand_head(), which may move the skb head. The pskb_expand_head()
contract requires pointers into the skb header to be reloaded after the
call.
If the later skb_realloc_headroom() branch is not taken, SIT uses the
stale iph6 pointer to read the inner hop limit and DS field. That can
read from a freed skb head after the old head's remaining clone is
released.
Reload iph6 after the offload helper succeeds and before subsequent
reads from the inner IPv6 header. Keep the existing reload after
skb_realloc_headroom(), since that branch can also replace the skb.
CVSS Score
9.8
EPSS Score
0.006
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: Fix slab-out-of-bounds in mlx5_query_nic_vport_mac_list
mlx5_query_nic_vport_mac_list() sizes its firmware command buffer using
the PF's log_max_current_uc/mc_list capabilities. When querying a VF
vport with a larger configured max (via devlink), the firmware response
can overflow this buffer:
BUG: KASAN: slab-out-of-bounds in mlx5_query_nic_vport_mac_list+0x453/0x4c0 [mlx5_core]
Read of size 4 at addr ff1100013ffc8a12 by task kworker/u96:2/385
CPU: 12 UID: 0 PID: 385 Comm: kworker/u96:2 Not tainted 7.0.0-rc6+ #1 PREEMPT
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)
Workqueue: mlx5_esw_wq esw_vport_change_handler [mlx5_core]
Call Trace:
<TASK>
dump_stack_lvl+0x69/0xa0
print_report+0x176/0x4e4
kasan_report+0xc8/0x100
mlx5_query_nic_vport_mac_list+0x453/0x4c0 [mlx5_core]
esw_update_vport_addr_list+0x2e3/0xda0 [mlx5_core]
esw_vport_change_handle_locked+0xa1f/0x1060 [mlx5_core]
esw_vport_change_handler+0x6a/0x90 [mlx5_core]
process_one_work+0x87f/0x15e0
worker_thread+0x62b/0x1020
kthread+0x375/0x490
ret_from_fork+0x4dc/0x810
ret_from_fork_asm+0x11/0x20
</TASK>
Fix by querying the vport's own HCA caps to size the buffer correctly.
Refactor the function to allocate and return the MAC list internally,
removing the caller's dependency on knowing the correct max.
CVSS Score
8.7
EPSS Score
0.001
Published
2026-06-25
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