| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
perf/x86: Move event pointer setup earlier in x86_pmu_enable()
A production AMD EPYC system crashed with a NULL pointer dereference
in the PMU NMI handler:
BUG: kernel NULL pointer dereference, address: 0000000000000198
RIP: x86_perf_event_update+0xc/0xa0
Call Trace:
<NMI>
amd_pmu_v2_handle_irq+0x1a6/0x390
perf_event_nmi_handler+0x24/0x40
The faulting instruction is `cmpq $0x0, 0x198(%rdi)` with RDI=0,
corresponding to the `if (unlikely(!hwc->event_base))` check in
x86_perf_event_update() where hwc = &event->hw and event is NULL.
drgn inspection of the vmcore on CPU 106 showed a mismatch between
cpuc->active_mask and cpuc->events[]:
active_mask: 0x1e (bits 1, 2, 3, 4)
events[1]: 0xff1100136cbd4f38 (valid)
events[2]: 0x0 (NULL, but active_mask bit 2 set)
events[3]: 0xff1100076fd2cf38 (valid)
events[4]: 0xff1100079e990a90 (valid)
The event that should occupy events[2] was found in event_list[2]
with hw.idx=2 and hw.state=0x0, confirming x86_pmu_start() had run
(which clears hw.state and sets active_mask) but events[2] was
never populated.
Another event (event_list[0]) had hw.state=0x7 (STOPPED|UPTODATE|ARCH),
showing it was stopped when the PMU rescheduled events, confirming the
throttle-then-reschedule sequence occurred.
The root cause is commit 7e772a93eb61 ("perf/x86: Fix NULL event access
and potential PEBS record loss") which moved the cpuc->events[idx]
assignment out of x86_pmu_start() and into step 2 of x86_pmu_enable(),
after the PERF_HES_ARCH check. This broke any path that calls
pmu->start() without going through x86_pmu_enable() -- specifically
the unthrottle path:
perf_adjust_freq_unthr_events()
-> perf_event_unthrottle_group()
-> perf_event_unthrottle()
-> event->pmu->start(event, 0)
-> x86_pmu_start() // sets active_mask but not events[]
The race sequence is:
1. A group of perf events overflows, triggering group throttle via
perf_event_throttle_group(). All events are stopped: active_mask
bits cleared, events[] preserved (x86_pmu_stop no longer clears
events[] after commit 7e772a93eb61).
2. While still throttled (PERF_HES_STOPPED), x86_pmu_enable() runs
due to other scheduling activity. Stopped events that need to
move counters get PERF_HES_ARCH set and events[old_idx] cleared.
In step 2 of x86_pmu_enable(), PERF_HES_ARCH causes these events
to be skipped -- events[new_idx] is never set.
3. The timer tick unthrottles the group via pmu->start(). Since
commit 7e772a93eb61 removed the events[] assignment from
x86_pmu_start(), active_mask[new_idx] is set but events[new_idx]
remains NULL.
4. A PMC overflow NMI fires. The handler iterates active counters,
finds active_mask[2] set, reads events[2] which is NULL, and
crashes dereferencing it.
Move the cpuc->events[hwc->idx] assignment in x86_pmu_enable() to
before the PERF_HES_ARCH check, so that events[] is populated even
for events that are not immediately started. This ensures the
unthrottle path via pmu->start() always finds a valid event pointer. |
| A NULL pointer dereference in Nitro PDF Pro for Windows v14.41.1.4 allows attackers to cause a Denial of Service (DoS) via a crafted XFA packet. |
| In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix NULL pointer dereference in netfs_unbuffered_write() on retry
When a write subrequest is marked NETFS_SREQ_NEED_RETRY, the retry path
in netfs_unbuffered_write() unconditionally calls stream->prepare_write()
without checking if it is NULL.
Filesystems such as 9P do not set the prepare_write operation, so
stream->prepare_write remains NULL. When get_user_pages() fails with
-EFAULT and the subrequest is flagged for retry, this results in a NULL
pointer dereference at fs/netfs/direct_write.c:189.
Fix this by mirroring the pattern already used in write_retry.c: if
stream->prepare_write is NULL, skip renegotiation and directly reissue
the subrequest via netfs_reissue_write(), which handles iterator reset,
IN_PROGRESS flag, stats update and reissue internally. |
| The md driver (drivers/md/md.c) in the Linux kernel before 2.6.30.2 might allow local users to cause a denial of service (NULL pointer dereference) via vectors related to "suspend_* sysfs attributes" and the (1) suspend_lo_store or (2) suspend_hi_store functions. NOTE: this is only a vulnerability when sysfs is writable by an attacker. |
| FileZilla Server before 0.9.22 allows remote attackers to cause a denial of service (crash) via a wildcard argument to the (1) LIST or (2) NLST commands, which results in a NULL pointer dereference, a different set of vectors than CVE-2006-6564. NOTE: CVE analysis suggests that the problem might be due to a malformed PORT command. |
| The Exchange Collaboration Data Objects (EXCDO) functionality in Microsoft Exchange Server 2000 SP3, 2003 SP1 and SP2, and 2007 allows remote attackers to cause a denial of service (crash) via an Internet Calendar (iCal) file containing multiple X-MICROSOFT-CDO-MODPROPS (MODPROPS) properties in which the second MODPROPS is longer than the first, which triggers a NULL pointer dereference and an unhandled exception. |
| axigen 1.2.6 through 2.0.0b1 does not properly parse login credentials, which allows remote attackers to cause a denial of service (NULL dereference and application crash) via a base64-encoded "*\x00" sequence on the imap port (143/tcp). |
| The _gnutls_recv_client_kx_message function in lib/gnutls_kx.c in libgnutls in gnutls-serv in GnuTLS before 2.2.4 continues to process Client Hello messages within a TLS message after one has already been processed, which allows remote attackers to cause a denial of service (NULL dereference and crash) via a TLS message containing multiple Client Hello messages, aka GNUTLS-SA-2008-1-2. |
| The Linux kernel before 2.6.25.10 does not properly perform tty operations, which allows local users to cause a denial of service (system crash) or possibly gain privileges via vectors involving NULL pointer dereference of function pointers in (1) hamradio/6pack.c, (2) hamradio/mkiss.c, (3) irda/irtty-sir.c, (4) ppp_async.c, (5) ppp_synctty.c, (6) slip.c, (7) wan/x25_asy.c, and (8) wireless/strip.c in drivers/net/. |
| Skulltag before 0.97d2-RC6 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) by sending a "command 29" packet when the player is not in the game. |
| The inotify functionality in Linux kernel 2.6 before 2.6.28-rc5 might allow local users to gain privileges via unknown vectors related to race conditions in inotify watch removal and umount. |
| cupsd in CUPS 1.3.9 and earlier allows local users, and possibly remote attackers, to cause a denial of service (daemon crash) by adding a large number of RSS Subscriptions, which triggers a NULL pointer dereference. NOTE: this issue can be triggered remotely by leveraging CVE-2008-5184. |
| The JBIG2 decoder in Xpdf 3.02pl2 and earlier, CUPS 1.3.9 and earlier, Poppler before 0.10.6, and other products allows remote attackers to cause a denial of service (crash) via a crafted PDF file that triggers a NULL pointer dereference. |
| The multipart processor in ModSecurity before 2.5.9 allows remote attackers to cause a denial of service (crash) via a multipart form datapost request with a missing part header name, which triggers a NULL pointer dereference. |
| The Linux kernel 2.6.0 through 2.6.30.4, and 2.4.4 through 2.4.37.4, does not initialize all function pointers for socket operations in proto_ops structures, which allows local users to trigger a NULL pointer dereference and gain privileges by using mmap to map page zero, placing arbitrary code on this page, and then invoking an unavailable operation, as demonstrated by the sendpage operation (sock_sendpage function) on a PF_PPPOX socket. |
| The udp_sendmsg function in the UDP implementation in (1) net/ipv4/udp.c and (2) net/ipv6/udp.c in the Linux kernel before 2.6.19 allows local users to gain privileges or cause a denial of service (NULL pointer dereference and system crash) via vectors involving the MSG_MORE flag and a UDP socket. |
| libpurple/protocols/irc/msgs.c in the IRC protocol plugin in libpurple in Pidgin before 2.6.2 allows remote IRC servers to cause a denial of service (NULL pointer dereference and application crash) via a TOPIC message that lacks a topic string. |
| The checkHTTPpassword function in http.c in ntop 3.3.10 and earlier allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an Authorization HTTP header that lacks a : (colon) character in the base64-decoded string. |
| The init_posix_timers function in kernel/posix-timers.c in the Linux kernel before 2.6.31-rc6 allows local users to cause a denial of service (OOPS) or possibly gain privileges via a CLOCK_MONOTONIC_RAW clock_nanosleep call that triggers a NULL pointer dereference. |
| The load_flat_shared_library function in fs/binfmt_flat.c in the flat subsystem in the Linux kernel before 2.6.31-rc6 allows local users to cause a denial of service (NULL pointer dereference and system crash) or possibly have unspecified other impact by executing a shared flat binary, which triggers an access of an "uninitialized cred pointer." |
