Linux: >> Linux Kernel >> 2.6.16.26 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mld: don't dereference a pointer before NULL checking it
In iwl_mld_remove_link, the link->fw_id is saved at the beginning of the
function so we have it after we freed the link.
But the link pointer can be NULL, and is not checked when the fw_id is
stored.
Fix it by simply freeing the link at the end of the function.
fFixes: 0e66a39f4f0e ("wifi: iwlwifi: fix potential use after free in iwl_mld_remove_link()")
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: bnep: Fix UAF read of dev->name
bnep_add_connection() needs to keep holding the bnep_session_sem while
reading dev->name (just like bnep_get_connlist() does); otherwise the
bnep_session() thread can concurrently free the net_device, which can for
example be triggered by a concurrent bnep_del_connection().
(This UAF is fairly uninteresting from a security perspective;
calling bnep_add_connection() requires passing a capable(CAP_NET_ADMIN)
check. It also requires completely tearing down a netdev during a fairly
tight race window.)
CVSS Score
8.8
EPSS Score
0.004
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
ipv4: raw: reject IP_HDRINCL packets with ihl < 5
raw_send_hdrinc() validates that the caller-supplied IPv4 header
fits within the message length:
iphlen = iph->ihl * 4;
err = -EINVAL;
if (iphlen > length)
goto error_free;
if (iphlen >= sizeof(*iph)) {
/* fix up saddr, tot_len, id, csum, transport_header */
}
It does not, however, reject ihl < 5. For such a packet the
"if (iphlen >= sizeof(*iph))" branch is skipped, leaving the
crafted iphdr untouched, but the packet is still handed to
__ip_local_out() and onward. Downstream consumers that read
iph->ihl assume a sane value: net/ipv4/ah4.c:ah_output() in
particular subtracts sizeof(struct iphdr) from top_iph->ihl * 4
and passes the (signed-int-negative, then cast to size_t)
result to memcpy(), producing an OOB access of length close to
SIZE_MAX and a host kernel panic.
An IPv4 header with ihl < 5 is malformed by definition (RFC 791:
"Internet Header Length is the length of the internet header in
32 bit words ... Note that the minimum value for a correct header
is 5."). The kernel should not be willing to inject such a
packet into its own output path.
Reject "iphlen < sizeof(*iph)" alongside the existing
"iphlen > length" check. This matches the principle that locally
constructed packets that re-enter the IP stack must pass the same
basic sanity tests that a foreign packet would be subjected to.
Once this lands, the "if (iphlen >= sizeof(*iph))" wrapper around
the fixup branch becomes redundant; left in place to keep the
patch minimal and backport-friendly. A follow-up can unwrap it.
Note that commit 86f4c90a1c5c ("ipv4, ipv6: ensure raw socket
message is big enough to hold an IP header") ensures the message
buffer is large enough to hold an iphdr, but does not constrain
the self-reported iph->ihl.
Reachability: the malformed packet source is any caller with
CAP_NET_RAW, including an unprivileged process in a user+net
namespace on a kernel with CONFIG_USER_NS=y. The reproduced AH
crash also requires a matching xfrm AH policy on the outgoing
route; a container granted CAP_NET_ADMIN can install that state
and policy in its netns. Loopback bypasses xfrm_output, so the
trigger uses a real netdev.
Reproduced on UML + KASAN: kernel-mode fault at addr 0x0 with
memcpy_orig at the crash site. Same shape reproduces inside a
rootless Docker container with --cap-add NET_ADMIN on a stock
distro kernel.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: reject oversized group bitmap descriptors
ocfs2_validate_gd_parent() only bounds bg_bits against the parent
allocator's chain geometry. A malicious descriptor can still claim a
bg_size/bg_bits pair that exceeds the bitmap bytes that physically fit in
the group descriptor block, so later bitmap scans and bit updates can run
past bg_bitmap.
Add a physical-cap check based on ocfs2_group_bitmap_size() for the parent
allocator type and reject descriptors whose bg_size or bg_bits exceed that
capacity. Keep the existing chain geometry check so both the on-disk
bitmap layout and the allocator metadata must agree before the descriptor
is used.
Validation reproduced this kernel report:
KASAN use-after-free in _find_next_bit+0x7f/0xc0
Read of size 8
Call trace:
dump_stack_lvl+0x66/0xa0 (?:?)
print_report+0xd0/0x630 (?:?)
_find_next_bit+0x7f/0xc0 (?:?)
srso_alias_return_thunk+0x5/0xfbef5 (?:?)
__virt_addr_valid+0x188/0x2f0 (?:?)
kasan_report+0xe4/0x120 (?:?)
ocfs2_find_max_contig_free_bits+0x35/0x70 (fs/ocfs2/suballoc.c:1375)
ocfs2_block_group_set_bits+0x472/0x4b0 (fs/ocfs2/suballoc.c:1457)
ocfs2_cluster_group_search+0x16b/0x440 (fs/ocfs2/suballoc.c:86)
ocfs2_bg_discontig_fix_result+0x1ef/0x230 (fs/ocfs2/suballoc.c:1786)
ocfs2_search_chain+0x8f8/0x10a0 (fs/ocfs2/suballoc.c:1886)
get_page_from_freelist+0x70e/0x2370 (?:?)
lock_release+0xc6/0x290 (?:?)
do_raw_spin_unlock+0x9a/0x100 (?:?)
kasan_unpoison+0x27/0x60 (?:?)
__bfs+0x147/0x240 (?:?)
get_page_from_freelist+0x83d/0x2370 (?:?)
ocfs2_claim_suballoc_bits+0x38c/0xe70 (fs/ocfs2/suballoc.c:96)
sched_domains_numa_masks_clear+0x70/0xd0 (?:?)
check_irq_usage+0xe8/0xb70 (?:?)
__ocfs2_claim_clusters+0x18d/0x4c0 (fs/ocfs2/suballoc.c:2497)
check_path+0x24/0x50 (?:?)
rcu_is_watching+0x20/0x50 (?:?)
check_prev_add+0xfd/0xd00 (?:?)
ocfs2_add_clusters_in_btree+0x17d/0x810 (fs/ocfs2/suballoc.c:?)
__folio_batch_add_and_move+0x1f5/0x3d0 (?:?)
ocfs2_add_inode_data+0xd9/0x120 (fs/ocfs2/suballoc.c:?)
filemap_add_folio+0x105/0x1f0 (?:?)
ocfs2_write_begin_nolock+0x29f7/0x2f80 (fs/ocfs2/suballoc.c:3043)
ocfs2_read_inode_block+0xb5/0x110 (fs/ocfs2/suballoc.c:?)
down_write+0xf5/0x180 (?:?)
ocfs2_write_begin+0x180/0x240 (fs/ocfs2/suballoc.c:?)
__mark_inode_dirty+0x758/0x9a0 (?:?)
inode_to_bdi+0x41/0x90 (?:?)
balance_dirty_pages_ratelimited_flags+0xf8/0x1d0 (?:?)
generic_perform_write+0x252/0x440 (?:?)
mnt_put_write_access_file+0x16/0x70 (?:?)
file_update_time_flags+0xe4/0x200 (?:?)
ocfs2_file_write_iter+0x80a/0x1320 (fs/ocfs2/suballoc.c:?)
lock_acquire+0x184/0x2f0 (?:?)
ksys_write+0xd2/0x170 (?:?)
apparmor_file_permission+0xf5/0x310 (?:?)
read_zero+0x8d/0x140 (?:?)
lock_is_held_type+0x8f/0x100 (?:?)
CVSS Score
8.8
EPSS Score
0.005
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
hdlc_ppp: sync per-proto timers before freeing hdlc state
Each PPP control protocol (LCP/IPCP/IPV6CP) embedded in struct ppp
registers a timer via timer_setup(). That struct ppp is the
hdlc->state allocation, which detach_hdlc_protocol() frees with kfree()
in both teardown paths: unregister_hdlc_device() and the re-attach inside
attach_hdlc_protocol().
The ppp proto never registered a .detach callback, so
detach_hdlc_protocol() performs no timer synchronization before the
kfree(). The only cancel, timer_delete(&proto->timer) in ppp_cp_event(),
is partial (it does not wait for a running callback) and only runs on the
->CLOSED transition; ppp_stop()/ppp_close() do not sync either. A
ppp_timer callback already executing (blocked on ppp->lock) survives the
kfree and then dereferences proto->state / ppp->lock in freed memory,
leading to a use-after-free.
Fix this by adding a .detach helper that calls timer_shutdown_sync() on
every per-proto timer. detach_hdlc_protocol() invokes proto->detach(dev)
before kfree(hdlc->state), so timer_shutdown_sync()
now runs on both free paths.
timer_shutdown_sync() is used instead of timer_delete_sync() because the
keepalive path re-arms the timer through add_timer()/mod_timer() and
shutdown blocks any re-activation during teardown.
Initialize the per-protocol timers in ppp_ioctl() when the protocol is
attached, and remove the now-redundant timer_setup() from ppp_start(), so
that the timers are initialized exactly once at attach time and
ppp_timer_release() never operates on uninitialized timer_list
structures. attach_hdlc_protocol() uses kmalloc() (not kzalloc), so
struct ppp's protos[i].timer is uninitialized garbage until the first
timer_setup(); without this init-at-attach, attaching the PPP protocol
without ever bringing the device up would leave timer_shutdown_sync()
operating on uninitialized memory in .detach. Moving the init out of
ppp_start() (which only runs on NETDEV_UP) into the attach path makes the
initialization unconditional and avoids initializing the same timer_list
twice.
This bug was found by static analysis.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
fbdev: Fix fb_new_modelist to prevent null-ptr-deref in fb_videomode_to_var
info->var, a framebuffer's current mode, is expected to have a matching
entry in info->modelist. var_to_display() relies on this and treats a
failed fb_match_mode() as "This should not happen". fb_set_var() keeps it
true by adding the mode to the list on every change, and
do_register_framebuffer() does the same at registration.
store_modes() replaces the modelist from userspace. fb_new_modelist()
validates the new modes but does not check that info->var still has a
match. It relies on fbcon_new_modelist() to re-point consoles, but that
only handles consoles mapped to the framebuffer. With fbcon unbound there
are none, so info->var is left describing a mode that is no longer in the
list.
A later console takeover runs var_to_display(), where fb_match_mode()
returns NULL and leaves fb_display[i].mode NULL. fbcon_switch() passes it
to display_to_var(), and fb_videomode_to_var() dereferences the NULL mode.
Keep the current mode in the list in fb_new_modelist(), the same way
fb_set_var() does.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix posix_acl leak on SETACL decode failure
nfsaclsvc_decode_setaclargs() and nfs3svc_decode_setaclargs() each
call nfs_stream_decode_acl() twice, first for NFS_ACL and then for
NFS_DFACL. Each successful call transfers ownership of a freshly
allocated posix_acl into argp->acl_access or argp->acl_default. If
the first call succeeds but the second fails, the decoder returns
false and argp->acl_access is left dangling.
ACLPROC2_SETACL.pc_release was wired to nfssvc_release_attrstat and
ACLPROC3_SETACL.pc_release was wired to nfs3svc_release_fhandle.
Both only call fh_put() and have no knowledge of the ACL fields on
argp. The posix_acl_release() pairs sat at the out: labels inside
nfsacld_proc_setacl() and nfsd3_proc_setacl(), but svc_process()
skips pc_func when pc_decode returns false, so that cleanup is
unreachable on decode failure:
svc_process_common()
pc_decode() /* decode_setaclargs: false */
/* pc_func skipped */
pc_release() /* fh_put only -- ACLs leaked */
The orphaned posix_acl is leaked for the lifetime of the server.
Fix by adding nfsaclsvc_release_setacl() and nfs3svc_release_setacl(),
which release both argp->acl_access and argp->acl_default in addition
to fh_put(), and wiring them as pc_release for their respective SETACL
procedures. pc_release runs on every path svc_process() takes after
decode, including decode failure, so the posix_acl_release() pairs are
removed from the proc functions' out: labels to keep ownership in one
place. This matches the existing release_getacl() pattern used by
the sibling GETACL procedures.
CVSS Score
7.5
EPSS Score
0.005
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
udf: reject descriptors with oversized CRC length
udf_read_tagged() skips CRC verification when descCRCLength +
sizeof(struct tag) exceeds the block size. A crafted UDF image can
set descCRCLength to an oversized value to bypass CRC validation
entirely; the descriptor is then accepted based solely on the 8-bit
tag checksum, which is trivially recomputable.
Reject such descriptors instead of silently accepting them. A
legitimate single-block descriptor should never have a CRC length that
exceeds the block.
CVSS Score
8.4
EPSS Score
0.002
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
ipv6: mcast: Fix use-after-free when processing MLD queries
When processing an MLD query, a pointer to the multicast group address
is retrieved when initially parsing the packet. This pointer is later
dereferenced without being reloaded despite the fact that the skb header
might have been reallocated following the pskb_may_pull() calls, leading
to a use-after-free [1].
Fix by copying the multicast group address when the packet is initially
parsed.
[1]
BUG: KASAN: slab-use-after-free in __mld_query_work (net/ipv6/mcast.c:1512)
Read of size 8 at addr ffff8881154b8e90 by task kworker/4:1/118
Workqueue: mld mld_query_work
Call Trace:
<TASK>
dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)
print_address_description.constprop.0 (mm/kasan/report.c:378)
print_report (mm/kasan/report.c:482)
kasan_report (mm/kasan/report.c:595)
__mld_query_work (net/ipv6/mcast.c:1512)
mld_query_work (net/ipv6/mcast.c:1563)
process_one_work (kernel/workqueue.c:3314)
worker_thread (kernel/workqueue.c:3397 kernel/workqueue.c:3478)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:158)
ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
</TASK>
[...]
Freed by task 118:
kasan_save_stack (mm/kasan/common.c:57)
kasan_save_track (mm/kasan/common.c:78)
kasan_save_free_info (mm/kasan/generic.c:584)
__kasan_slab_free (mm/kasan/common.c:253 mm/kasan/common.c:285)
kfree (./include/linux/kasan.h:235 mm/slub.c:2689 mm/slub.c:6251 mm/slub.c:6566)
pskb_expand_head (net/core/skbuff.c:2335)
__pskb_pull_tail (net/core/skbuff.c:2878 (discriminator 4))
__mld_query_work (net/ipv6/mcast.c:1495 (discriminator 1))
mld_query_work (net/ipv6/mcast.c:1563)
process_one_work (kernel/workqueue.c:3314)
worker_thread (kernel/workqueue.c:3397 kernel/workqueue.c:3478)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:158)
ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
CVSS Score
8.8
EPSS Score
0.003
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: bnep: reject short frames before parsing
A BNEP peer can send a short BNEP SDU. bnep_rx_frame() reads the
packet type byte immediately and, for control packets, reads the control
opcode and setup UUID-size byte before proving that those bytes are
present. bnep_rx_control() also dereferences the control opcode without
rejecting an empty control payload.
Use skb_pull_data() for the fixed fields in bnep_rx_frame() so a NULL
return gates each dereference. Split the control handler so the frame
path can pass an opcode that has already been pulled, and keep the
byte-buffer wrapper for extension control payloads.
For BNEP_SETUP_CONN_REQ, name the UUID-size byte before pulling the
setup payload. struct bnep_setup_conn_req carries destination and source
service UUIDs after that byte, each uuid_size bytes, so the parser now
documents that tuple explicitly instead of leaving the pull length as an
opaque multiplication.
Validation reproduced this kernel report:
KASAN slab-out-of-bounds in bnep_rx_frame.isra.0+0x130c/0x1790
The buggy address belongs to the object at ffff88800c0f7908 which belongs
to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes to the right of allocated 1-byte
region [ffff88800c0f7908, ffff88800c0f7909)
Read of size 1
Call trace:
dump_stack_lvl+0xb3/0x140 (?:?)
print_address_description+0x57/0x3a0 (?:?)
bnep_rx_frame+0x130c/0x1790 (net/bluetooth/bnep/core.c:306)
print_report+0xb9/0x2b0 (?:?)
__virt_addr_valid+0x1ba/0x3a0 (?:?)
srso_alias_return_thunk+0x5/0xfbef5 (?:?)
kasan_addr_to_slab+0x21/0x60 (?:?)
kasan_report+0xe0/0x110 (?:?)
process_one_work+0xfce/0x17e0 (kernel/workqueue.c:3200)
worker_thread+0x65c/0xe40 (?:?)
__kthread_parkme+0x184/0x230 (?:?)
kthread+0x35e/0x470 (?:?)
_raw_spin_unlock_irq+0x28/0x50 (?:?)
ret_from_fork+0x586/0x870 (?:?)
__switch_to+0x74f/0xdc0 (?:?)
ret_from_fork_asm+0x1a/0x30 (?:?)
CVSS Score
7.1
EPSS Score
0.003
Published
2026-06-25