Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
nfsd: reset write verifier on deferred writeback errors
nfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to
detect deferred writeback errors, but neither rotates the server's write
verifier (nn->writeverf) when this check fails. Every other
durable-storage-failure path in these functions calls
commit_reset_write_verifier() before returning an error.
The missing rotation means clients holding UNSTABLE write data under the
current verifier will COMMIT, receive the unchanged verifier back, and
conclude their data is durable — silently dropping data that failed
writeback. This violates the UNSTABLE+COMMIT durability contract
(RFC 1813 §3.3.7, RFC 8881 §18.32).
Add commit_reset_write_verifier() calls at both filemap_check_wb_err()
error sites, matching the pattern used by adjacent error paths in the
same functions. The helper already filters -EAGAIN and -ESTALE
internally, so the calls are unconditionally safe.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race
When find_or_alloc_open_stateowner() encounters an unconfirmed owner, it
calls release_openowner() and sets oo = NULL. Control then falls through
past the `if (oo)` guard -- which would have freed any pre-allocated
`new` -- and unconditionally executes `new = alloc_stateowner(...)`. If
`new` was already allocated on a prior iteration, the pointer is
silently overwritten and the previous allocation (slab object + owner
name buffer) is leaked.
This requires a race: two NFSv4.0 OPEN threads with the same owner
string, where a concurrent thread inserts a new unconfirmed owner into
the hash between retry iterations. The window is narrow but repeatable
under adversarial conditions.
Fix by adding `goto retry` after `oo = NULL` so the already-allocated
`new` is reused on the next iteration rather than overwritten.
CVSS Score
7.5
EPSS Score
0.004
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix dead ACL conflict guard in nfsd4_create
nfsd4_create() steals create->cr_dpacl/cr_pacl into the local
nfsd_attrs via the designated initializer, then immediately sets the
source pointers to NULL. The subsequent conflict guard tests the
already-nilled source fields, making it permanently dead code:
if (create->cr_acl) {
if (create->cr_dpacl || create->cr_pacl) /* always false */
When a client encodes both FATTR4_WORD0_ACL and
FATTR4_WORD2_POSIX_{DEFAULT,ACCESS}_ACL in the same CREATE fattr
bitmap, nfsd4_acl_to_attr() overwrites attrs.na_pacl/na_dpacl without
releasing the originals, leaking two posix_acl slab objects per
request. Repeated requests cause unbounded slab exhaustion.
Fix by checking attrs.na_dpacl/na_pacl (the stolen values) instead of
the nilled create->cr_dpacl/cr_pacl, matching the correct pattern
already used in nfsd4_setattr().
CVSS Score
7.5
EPSS Score
0.003
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix posix_acl leak and ignored error in nfsd4_create_file
nfsd4_create_file() has two bugs in its ACL handling:
The return value of nfsd4_acl_to_attr() is silently discarded. When
the NFSv4-to-POSIX ACL conversion fails (e.g., -EINVAL for
unsupported ACE types), the file is created without any ACL and the
client receives NFS4_OK. This violates RFC 7530/8881 which require
the server to reject unsupported attributes on CREATE.
When start_creating() fails after ACL attributes have been populated
in attrs (either via nfsd4_acl_to_attr or via ownership transfer from
open->op_dpacl/op_pacl), the function jumps to out_write which skips
nfsd_attrs_free(). The posix_acl allocations are leaked. A client
can trigger this repeatedly with OPEN(CREATE), ACL attributes, and an
invalid filename (e.g., longer than NAME_MAX).
Fix both by capturing the nfsd4_acl_to_attr() return value and by
changing the early error paths to jump to out instead of out_write.
Initialize child to ERR_PTR(-EINVAL) so that end_creating() is safe
to call even if start_creating() was never reached.
CVSS Score
7.1
EPSS Score
0.003
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:
NFSD: Fix SECINFO_NO_NAME decode error cleanup
nfsd4_decode_secinfo_no_name() currently initializes sin_exp after
decoding sin_style. If the XDR stream is truncated, the decoder returns
nfserr_bad_xdr before sin_exp is initialized.
Since commit 3fdc54646234 ("NFSD: Reduce amount of struct
nfsd4_compoundargs that needs clearing"), the inline iops array is not
cleared between RPC calls. A failed SECINFO_NO_NAME decode can therefore
leave sin_exp holding stale union contents from a previous operation.
The error response path still invokes nfsd4_secinfo_no_name_release(),
which calls exp_put() on a non-NULL sin_exp.
Initialize sin_exp before the first failable decode step, matching
nfsd4_decode_secinfo().
CVSS Score
9.8
EPSS Score
0.005
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: reject non-VALID session in compound request branch
smb2_check_user_session() takes a shortcut for any operation that is not
the first in a COMPOUND request: it reuses work->sess (the session bound by
the first operation) and validates only the SessionId, then returns
"valid". It never re-checks work->sess->state == SMB2_SESSION_VALID, and a
SessionId of 0xFFFFFFFFFFFFFFFF (ULLONG_MAX, the MS-SMB2 related-operation
value) skips even the id comparison. The standalone path
(ksmbd_session_lookup_all() plus the SESSION_SETUP state machine) does
enforce the VALID state; the compound branch bypasses all of it.
A SESSION_SETUP carrying only an NTLM Type-1 (NtLmNegotiate) blob publishes
a fresh SMB2_SESSION_IN_PROGRESS session whose sess->user is still NULL
(->user is assigned later, by ntlm_authenticate()). Used as operation 1 of
a COMPOUND with operation 2 = TREE_CONNECT (related, SessionId=ULLONG_MAX,
\\host\IPC$), the tree-connect then runs on that IN_PROGRESS session and
reaches ksmbd_ipc_tree_connect_request(), which dereferences
user_name(sess->user) with sess->user == NULL (transport_ipc.c:687/701/704)
-> remote NULL-pointer dereference and a kernel Oops that wedges the ksmbd
worker for all clients.
Reject any non-first compound operation that lands on a session which is
not SMB2_SESSION_VALID, mirroring the validity the standalone lookup path
enforces. SESSION_SETUP itself legitimately runs on an IN_PROGRESS session,
but it is never carried as a non-first compound operation, so multi-leg
authentication is unaffected by this check.
CVSS Score
7.5
EPSS Score
0.007
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
serial: 8250_dw: unregister 8250 port if clk_notifier_register() fails
dw8250_probe() registers the 8250 port via serial8250_register_8250_port()
and then, if the device has a clock, registers a clock notifier. If
clk_notifier_register() fails, probe returns the error but leaves the
8250 port registered. The matching serial8250_unregister_port() lives
in dw8250_remove(), which is not called when probe fails, so the port
slot stays occupied until the device is rebound or the system is
rebooted. The devm-allocated driver data is freed while the port still
references it (via the saved private_data and serial_in/serial_out
callbacks), so any access to that port slot before a rebind is a
use-after-free hazard.
Unregister the port on the clk_notifier_register() error path.
CVSS Score
9.8
EPSS Score
0.005
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
vc_screen: fix null-ptr-deref in vcs_notifier() during concurrent vcs_write
A KASAN null-ptr-deref was observed in vcs_notifier():
BUG: KASAN: null-ptr-deref in vcs_notifier+0x98/0x130
Read of size 2 at addr qmp_cmd_name: qmp_capabilities, arguments: {}
The issue is a race condition in vcs_write(). When the console_lock is
temporarily dropped (to copy data from userspace), the vc_data pointer
obtained from vcs_vc() may become stale. After re-acquiring the lock,
vcs_vc() is called again to re-validate the pointer. If the vc has been
deallocated in the meantime, vcs_vc() returns NULL, and the while loop
breaks (with written > 0). However, after the loop, vcs_scr_updated(vc)
is still called with the now-NULL vc pointer, leading to a null pointer
dereference in the notifier chain (vcs_notifier dereferences param->vc).
Fix this by adding a NULL check for vc before calling vcs_scr_updated().
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
iio: adc: ti-ads1298: add bounds check to pga_settings index
ads1298_pga_settings has 7 elements but ADS1298_MASK_CH_PGA can yield
values 0-7. If it yields a value >= 7, this causes an out-of-bounds
array access. Add a bounds check and return -EINVAL if the index
is out of range.
Note that the remaining value b111 is reserved so should not be seen
in a correctly functioning system.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-19