Summary
Jean-Claude Graf, Sandro Rüegge, Ali Hajiabadi, and Kaveh Razavi discovered
that the Linux kernel contained insufficient branch predictor isolation
between a guest and a userspace hypervisor for certain processors. This
flaw is known as VMSCAPE. An attacker in a guest VM could possibly use this
to expose sensitive information from the host OS. (CVE-2025-40300)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- Cryptographic API;
- HSI subsystem;
- Media drivers;
- Network drivers;
- Bluetooth subsystem;
- Timer subsystem;
- Memory management;
- Appletalk network protocol;
- Netfilter;
- TLS protocol;
(CVE-2025-21729, CVE-2025-37838, CVE-2025-37958, CVE-2025-38118,
CVE-2025-38227, CVE-2025-38352, CVE-2025-38616, CVE-2025-38666,
CVE-2025-38678, CVE-2025-39964, CVE-2025-39993, CVE-2025-40018)
Fixed packages 2
| Release | Package | Fixed in |
|---|---|---|
| Ubuntu · 22.04 LTS 22.04:LTS | linux-azure-6.8 | 6.8.0-1044.50~22.04.1 |
| Ubuntu · 24.04 LTS 24.04:LTS | linux-azure | 6.8.0-1044.50 |
Vulnerabilities 13
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High 7.8
posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del()
In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del() If an exiting non-autoreaping task has already passed exit_notify() and calls handle_posix_cpu_timers() …
KEV Sep 4, 2025 -
High 7.8
crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg
In the Linux kernel, the following vulnerability has been resolved: crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg Issuing two writes to the same af_alg socket is bogus as the data will be interleaved in an unpredictable fashion. Furthermore, c…
KEV Sep 18, 2026 -
High 7.8
wifi: rtw89: fix race between cancel_hw_scan and hw_scan completion
In the Linux kernel, the following vulnerability has been resolved: wifi: rtw89: fix race between cancel_hw_scan and hw_scan completion The rtwdev->scanning flag isn't protected by mutex originally, so cancel_hw_scan can pass the condition, but suddenly hw_sc…
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High 7.8
HSI: ssi_protocol: Fix use after free vulnerability in ssi_protocol Driver Due to Race Condition
In the Linux kernel, the following vulnerability has been resolved: HSI: ssi_protocol: Fix use after free vulnerability in ssi_protocol Driver Due to Race Condition In the ssi_protocol_probe() function, &ssi->work is bound with ssip_xmit_work(), In ssip_pn_se…
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High 7.8
Bluetooth: MGMT: Fix UAF on mgmt_remove_adv_monitor_complete
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: MGMT: Fix UAF on mgmt_remove_adv_monitor_complete This reworks MGMT_OP_REMOVE_ADV_MONITOR to not use mgmt_pending_add to avoid crashes like bellow: ================================…
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High 7.8
media: vidtv: Terminating the subsequent process of initialization failure
In the Linux kernel, the following vulnerability has been resolved: media: vidtv: Terminating the subsequent process of initialization failure syzbot reported a slab-use-after-free Read in vidtv_mux_init. [1] After PSI initialization fails, the si member is a…
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High 7.8
tls: handle data disappearing from under the TLS ULP
In the Linux kernel, the following vulnerability has been resolved: tls: handle data disappearing from under the TLS ULP TLS expects that it owns the receive queue of the TCP socket. This cannot be guaranteed in case the reader of the TCP socket entered befor…
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High 7.8CVE-2025-38678 Public exploit
netfilter: nf_tables: reject duplicate device on updates
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: reject duplicate device on updates A chain/flowtable update with duplicated devices in the same batch is possible. Unfortunately, netdev event path only removes the firs…
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High 7.8
media: rc: fix races with imon_disconnect()
In the Linux kernel, the following vulnerability has been resolved: media: rc: fix races with imon_disconnect() Syzbot reports a KASAN issue as below: BUG: KASAN: use-after-free in __create_pipe include/linux/usb.h:1945 [inline] BUG: KASAN: use-after-free in …
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High 7.8
ipvs: Defer ip_vs_ftp unregister during netns cleanup
In the Linux kernel, the following vulnerability has been resolved: ipvs: Defer ip_vs_ftp unregister during netns cleanup On the netns cleanup path, __ip_vs_ftp_exit() may unregister ip_vs_ftp before connections with valid cp->app pointers are flushed, leadin…
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Unscored —
mm/huge_memory: fix dereferencing invalid pmd migration entry
In the Linux kernel, the following vulnerability has been resolved: mm/huge_memory: fix dereferencing invalid pmd migration entry When migrating a THP, concurrent access to the PMD migration entry during a deferred split scan can lead to an invalid address ac…
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Unscored —
net: appletalk: Fix use-after-free in AARP proxy probe
In the Linux kernel, the following vulnerability has been resolved: net: appletalk: Fix use-after-free in AARP proxy probe The AARP proxy‐probe routine (aarp_proxy_probe_network) sends a probe, releases the aarp_lock, sleeps, then re-acquires the lock. During…
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Unscored —
x86/vmscape: Add conditional IBPB mitigation
In the Linux kernel, the following vulnerability has been resolved: x86/vmscape: Add conditional IBPB mitigation VMSCAPE is a vulnerability that exploits insufficient branch predictor isolation between a guest and a userspace hypervisor (like QEMU). Existing …
References
-
report
https://ubuntu.com/security/CVE-2025-21729
-
report
https://ubuntu.com/security/CVE-2025-37838
-
report
https://ubuntu.com/security/CVE-2025-37958
-
report
https://ubuntu.com/security/CVE-2025-38118
-
report
https://ubuntu.com/security/CVE-2025-38227
-
report
https://ubuntu.com/security/CVE-2025-38352
-
report
https://ubuntu.com/security/CVE-2025-38616
-
report
https://ubuntu.com/security/CVE-2025-38666
-
report
https://ubuntu.com/security/CVE-2025-38678
-
report
https://ubuntu.com/security/CVE-2025-39964
-
report
https://ubuntu.com/security/CVE-2025-39993
-
report
https://ubuntu.com/security/CVE-2025-40018
-
report
https://ubuntu.com/security/CVE-2025-40300