Linux: >> Linux Kernel >> 2.6.38.5 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
staging: vme_user: bound slave read/write to the kern_buf size
The SLAVE-path helpers buffer_to_user() and buffer_from_user() copy
'count' bytes into/out of the fixed-size kern_buf (size_buf ==
PCI_BUF_SIZE == 0x20000, 128 KiB) using *ppos as the offset, without
bounding *ppos + count against size_buf.
vme_user_write()/vme_user_read() only clamp count to the VME window size
(image_size = vme_get_size(resource)), which VME_SET_SLAVE sets from the
user-supplied slave.size -- validated against the VME address space (up
to VME_A32_MAX = 4 GiB), not against PCI_BUF_SIZE. When the window
exceeds 128 KiB, a write()/read() copies past the kern_buf allocation.
Clamp count against size_buf in both helpers, with an early return when
*ppos is already at/after the buffer end. *ppos is >= 0 here (the caller
rejects negative offsets), so size_buf - *ppos cannot wrap. This mirrors
the existing clamp in the MASTER-path helpers resource_to_user() /
resource_from_user(), and matches the read()/write() convention of a
short transfer at end-of-buffer.
Found by static analysis (CodeQL taint tracking + CBMC bounded model
checking) and confirmed dynamically under KASAN with the vme_fake bridge:
BUG: KASAN: slab-out-of-bounds in _copy_from_user+0x2d/0x80
Write of size 262144 at addr ffff888004100000 by task trigger/68
_copy_from_user+0x2d/0x80
vme_user_write+0x13e/0x240 [vme_user]
vfs_write+0x1b8/0x7a0
ksys_write+0xb8/0x150
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
net: af_key: initialize alg_key_len for IPComp states
pfkey_msg2xfrm_state() handles the IPComp (SADB_X_SATYPE_IPCOMP) case by
allocating x->calg and copying only the algorithm name:
x->calg = kmalloc_obj(*x->calg);
if (!x->calg) {
err = -ENOMEM;
goto out;
}
strcpy(x->calg->alg_name, a->name);
x->props.calgo = sa->sadb_sa_encrypt;
Unlike the authentication (x->aalg) and encryption (x->ealg) branches of
the same function, the compression branch never initializes
calg->alg_key_len. IPComp carries no key and the allocation only
reserves sizeof(struct xfrm_algo) (i.e. no room for a key), so the field
is left containing uninitialized slab data.
calg->alg_key_len is later used as a length by xfrm_algo_clone() when an
IPComp state is cloned during XFRM_MSG_MIGRATE:
xfrm_state_migrate()
xfrm_state_clone_and_setup()
x->calg = xfrm_algo_clone(orig->calg);
kmemdup(orig, xfrm_alg_len(orig));
where xfrm_alg_len() returns sizeof(*alg) + (alg_key_len + 7) / 8. With
a non-zero garbage alg_key_len, kmemdup() reads past the end of the
68-byte calg object. Adding an IPComp SA via PF_KEY and then migrating
it triggers (net-next, KASAN, init_on_alloc=0):
BUG: KASAN: slab-out-of-bounds in kmemdup_noprof+0x44/0x60
Read of size 4164 at addr ff11000025a74980 by task diag2/9287
CPU: 3 UID: 0 PID: 9287 Comm: diag2 7.1.0-rc6-g903db046d557 #1
Call Trace:
<TASK>
dump_stack_lvl+0x10e/0x1f0
print_report+0xf7/0x600
kasan_report+0xe4/0x120
kasan_check_range+0x105/0x1b0
__asan_memcpy+0x23/0x60
kmemdup_noprof+0x44/0x60
xfrm_state_migrate+0x70a/0x1da0
xfrm_migrate+0x753/0x18a0
xfrm_do_migrate+0xb47/0xf10
xfrm_user_rcv_msg+0x411/0xb50
netlink_rcv_skb+0x158/0x420
xfrm_netlink_rcv+0x71/0x90
netlink_unicast+0x584/0x850
netlink_sendmsg+0x8b0/0xdc0
____sys_sendmsg+0x9f7/0xb90
___sys_sendmsg+0x134/0x1d0
__sys_sendmsg+0x16d/0x220
do_syscall_64+0x116/0x7d0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
Allocated by task 9287:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
__kasan_kmalloc+0xaa/0xb0
pfkey_add+0x2652/0x2ea0
pfkey_process+0x6d0/0x830
pfkey_sendmsg+0x42c/0x850
__sys_sendto+0x461/0x4b0
__x64_sys_sendto+0xe0/0x1c0
do_syscall_64+0x116/0x7d0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ff11000025a74980
which belongs to the cache kmalloc-96 of size 96
The buggy address is located 0 bytes inside of
allocated 68-byte region [ff11000025a74980, ff11000025a749c4)
Depending on the uninitialized value the same field can instead request
an oversized kmemdup() allocation and make the migration clone fail.
The XFRM netlink path is not affected: verify_one_alg() rejects an
XFRMA_ALG_COMP attribute shorter than xfrm_alg_len(), so a calg added via
XFRM_MSG_NEWSA is always self-consistent.
Initialize calg->alg_key_len to 0, matching the aalg/ealg branches.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes
Reject invalid `net.ipv4.tcp_reordering` values before they reach TCP
socket state. The sysctl is stored as an `int` but copied into the
`u32` `tp->reordering` field for new sockets, so negative writes wrap
to large values.
With `tcp_mtu_probing=2`, the wrapped value can overflow the
`tcp_mtu_probe()` size calculation and drive the MTU probing path into
an out-of-bounds read. Route `tcp_reordering` writes through
`proc_dointvec_minmax()` and require it to be at least 1. Also require
`tcp_max_reordering` to be at least 1 so the configured maximum cannot
become negative either.
When registering the table for a non-init network namespace, relocate
`extra2` pointers that refer into `init_net.ipv4` so the
`tcp_reordering` upper bound follows that namespace's
`tcp_max_reordering`.
Harden `tcp_mtu_probe()` itself by computing `size_needed` as `u64`.
This keeps the send queue and window checks from being bypassed through
signed integer overflow.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ebtables: zero chainstack array
sashiko reports:
looking at ebtables table
translation, could a sparse cpu_possible_mask lead to an uninitialized pointer
free?
If cpu_possible_mask is sparse (for example, CPU 0 and CPU 2 are possible,
but CPU 1 is not), the allocation loop skips CPU 1. If vmalloc_node() fails at
CPU 2, the cleanup loop will blindly decrement and call vfree() on
newinfo->chainstack[1].
Not a real-world bug, such allocation isn't expected to fail
in the first place.
CVSS Score
7.0
EPSS Score
0.001
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ebtables: terminate table name before find_table_lock()
update_counters() and compat_update_counters() forward a user-supplied
32-byte table name to find_table_lock() without NUL-terminating it. On a
lookup miss, find_inlist_lock() calls try_then_request_module(..., "%s%s",
"ebtable_", name), and vsnprintf() reads past the name field and the
stack object until it hits a zero byte.
BUG: KASAN: stack-out-of-bounds in string (lib/vsprintf.c:648 lib/vsprintf.c:730)
Read of size 1 at addr ffff8880119dfb20 by task exploit/147
Call Trace:
...
string (lib/vsprintf.c:648 lib/vsprintf.c:730)
vsnprintf (lib/vsprintf.c:2945)
__request_module (kernel/module/kmod.c:150)
do_update_counters.isra.0 (net/bridge/netfilter/ebtables.c:371 net/bridge/netfilter/ebtables.c:380)
update_counters (net/bridge/netfilter/ebtables.c:1440)
do_ebt_set_ctl (net/bridge/netfilter/ebtables.c:2573)
nf_setsockopt (net/netfilter/nf_sockopt.c:101)
ip_setsockopt (net/ipv4/ip_sockglue.c:1424)
raw_setsockopt (net/ipv4/raw.c:847)
__sys_setsockopt (net/socket.c:2393)
...
compat_do_replace() shares the same unterminated name via
compat_copy_ebt_replace_from_user(); terminate it there too so all
find_table_lock() callers behave alike. The other callers already
terminate the name after the copy.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
proc: protect ptrace_may_access() with exec_update_lock (part 1)
Fix the easy cases where procfs currently calls ptrace_may_access() without
exec_update_lock protection, where the fix is to simply add the extra lock
or use mm_access():
- do_task_stat(): grab exec_update_lock
- proc_pid_wchan(): grab exec_update_lock
- proc_map_files_lookup(): use mm_access() instead of get_task_mm()
- proc_map_files_readdir(): use mm_access() instead of get_task_mm()
- proc_ns_get_link(): grab exec_update_lock
- proc_ns_readlink(): grab exec_update_lock
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
cpufreq: pcc: fix use-after-free and double free in _OSC evaluation
pcc_cpufreq_do_osc() calls acpi_evaluate_object() twice for the
two-phase _OSC negotiation. Between the two calls it freed
output.pointer but left output.length unchanged. Since
acpi_evaluate_object() treats a non-zero length with a non-NULL
pointer as an existing buffer to write into, the second call wrote
into freed memory (use-after-free). The subsequent kfree(output.pointer)
at out_free then freed the same pointer a second time (double free).
Reset output.pointer to NULL and output.length to ACPI_ALLOCATE_BUFFER
after freeing the first result, so ACPICA allocates a fresh buffer for
each phase independently.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
proc: protect ptrace_may_access() with exec_update_lock (FD links)
proc_pid_get_link() and proc_pid_readlink() currently look up the task from
the pid once, then do the ptrace access check on that task, then look up
the task from the pid a second time to do the actual access.
That's racy in several ways.
To fix it, pass the task to the ->proc_get_link() handler, and instead of
proc_fd_access_allowed(), introduce a new helper call_proc_get_link() that
looks up and locks the task, does the access check, and calls
->proc_get_link().
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
posix-cpu-timers: Fix pid refcount leak in do_cpu_nanosleep() error path
In do_cpu_nanosleep(), posix_cpu_timer_create() takes a pid reference
via get_pid() and stores it in timer.it.cpu.pid. If the subsequent
posix_cpu_timer_set() call fails, the function returns immediately
without calling posix_cpu_timer_del() to release the pid reference,
causing a leak.
Fix it by calling posix_cpu_timer_del() before the unlock-and-return
on the error path, consistent with the other exit paths in the same
function.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: reject CLEAN_SEGMENTS ioctl with out-of-range segment numbers
Syzbot reported a hung task in nilfs_transaction_begin() where multiple
tasks performing chmod() on a nilfs2 mount blocked for over 143 seconds
waiting to acquire ns_segctor_sem for read:
INFO: task syz.0.17:5918 blocked for more than 143 seconds.
Call Trace:
schedule+0x164/0x360
rwsem_down_read_slowpath+0x6d9/0x940
down_read+0x99/0x2e0
nilfs_transaction_begin+0x364/0x710 fs/nilfs2/segment.c:221
nilfs_setattr+0x124/0x2c0 fs/nilfs2/inode.c:921
notify_change+0xc1a/0xf40
chmod_common+0x273/0x4a0
do_fchmodat+0x12d/0x230
The writer holding ns_segctor_sem was a concurrent
NILFS_IOCTL_CLEAN_SEGMENTS caller, stuck inside printk while emitting
per-element warnings from nilfs_sufile_updatev():
__nilfs_msg+0x373/0x450 fs/nilfs2/super.c:78
nilfs_sufile_updatev+0x21c/0x6d0 fs/nilfs2/sufile.c:186
nilfs_sufile_freev fs/nilfs2/sufile.h:93 [inline]
nilfs_free_segments fs/nilfs2/segment.c:1140 [inline]
nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1261 [inline]
nilfs_segctor_do_construct+0x1f55/0x76c0
nilfs_clean_segments+0x3bd/0xa50
nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:922 [inline]
nilfs_ioctl+0x261f/0x2780
The root cause is that user-supplied segment numbers are not validated
before nilfs_clean_segments() begins doing work; the range check on
each segnum is performed deep inside the call chain by
nilfs_sufile_updatev(), which emits a nilfs_warn() per invalid entry
while still holding the segctor lock and the sufile mi_sem. Under load
(repeated invocations across multiple mounts saturating the global
printk path), the cumulative printk latency keeps ns_segctor_sem held
long enough to trip the hung_task watchdog, blocking concurrent
operations such as chmod() that need ns_segctor_sem for read.
Fix by validating the contents of kbufs[4] in nilfs_clean_segments()
immediately after acquiring ns_segctor_sem via nilfs_transaction_lock().
Holding ns_segctor_sem serializes the check against
nilfs_ioctl_resize(), which can modify ns_nsegments, so the validation
uses a consistent value. Out-of-range segment numbers are rejected
with -EINVAL before any segment-cleaning work begins, so the bad
entries never reach the per-element diagnostic path inside
nilfs_sufile_updatev().
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-25
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