VulnerabilityPublished 4 Jul 2025Updated 31 Jul 2026

CVE-2025-38196: Linux kernel · io_uring/rsrc: validate buffer count with offset for cloning

Affects Linux kernelSource GCVE Database

Not known to be exploited · CVSS 5.5 Medium · fixed in 6.14.0-1015.15~24.04.1 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score

5.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 6.14.0-1015.15~24.04.1, 6.14.0-1014.14~24.04.1, 6.14.0-1007.7 +3

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Patches and advisories

Affected software

Product	Affected	Fixed in
Ubuntu 25.10linux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questing`Other threats	Affected 6.17.0-1003.3 – 6.17.0-1017.17 10 affected builds	Fixed in–
Ubuntu 24.04 LTSlinux-aws-6.14`pkg:deb/ubuntu/linux-aws-6.14?arch=source&distro=noble`Other threats	Affected <6.14.0-1015.15~24.04.1	Fixed in 6.14.0-1015.15~24.04.1
Ubuntu 24.04 LTSlinux-azure-6.11`pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=noble`Other threats	Affected 6.11.0-1008.8~24.04.1 – 6.11.0-1018.18~24.04.1 7 affected builds	Fixed in–
Ubuntu 24.04 LTSlinux-azure-6.14`pkg:deb/ubuntu/linux-azure-6.14?arch=source&distro=noble`Other threats	Affected <6.14.0-1014.14~24.04.1	Fixed in 6.14.0-1014.14~24.04.1
Ubuntu 24.04 LTSlinux-azure-nvidia-6.14`pkg:deb/ubuntu/linux-azure-nvidia-6.14?arch=source&distro=noble`Other threats	Affected <6.14.0-1007.7	Fixed in 6.14.0-1007.7
Ubuntu 24.04 LTSlinux-gcp-6.11`pkg:deb/ubuntu/linux-gcp-6.11?arch=source&distro=noble`Other threats	Affected 6.11.0-1006.6~24.04.2 – 6.11.0-1017.17~24.04.1 7 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring/rsrc: validate buffer count with offset for cloning syzbot reports that it can trigger a WARN_ON() for kmalloc() attempt that's too big: WARNING: CPU: 0 PID: 6488 at mm/slub.c:5024 __kvmalloc_node_noprof+0x520/0x640 mm/slub.c:5024 Modules linked in: CPU: 0 UID: 0 PID: 6488 Comm: syz-executor312 Not tainted 6.15.0-rc7-syzkaller-gd7fa1af5b33e #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __kvmalloc_node_noprof+0x520/0x640 mm/slub.c:5024 lr : __do_kmalloc_node mm/slub.c:-1 [inline] lr : __kvmalloc_node_noprof+0x3b4/0x640 mm/slub.c:5012 sp : ffff80009cfd7a90 x29: ffff80009cfd7ac0 x28: ffff0000dd52a120 x27: 0000000000412dc0 x26: 0000000000000178 x25: ffff7000139faf70 x24: 0000000000000000 x23: ffff800082f4cea8 x22: 00000000ffffffff x21: 000000010cd004a8 x20: ffff0000d75816c0 x19: ffff0000dd52a000 x18: 00000000ffffffff x17: ffff800092f39000 x16: ffff80008adbe9e4 x15: 0000000000000005 x14: 1ffff000139faf1c x13: 0000000000000000 x12: 0000000000000000 x11: ffff7000139faf21 x10: 0000000000000003 x9 : ffff80008f27b938 x8 : 0000000000000002 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 00000000ffffffff x4 : 0000000000400dc0 x3 : 0000000200000000 x2 : 000000010cd004a8 x1 : ffff80008b3ebc40 x0 : 0000000000000001 Call trace: __kvmalloc_node_noprof+0x520/0x640 mm/slub.c:5024 (P) kvmalloc_array_node_noprof include/linux/slab.h:1065 [inline] io_rsrc_data_alloc io_uring/rsrc.c:206 [inline] io_clone_buffers io_uring/rsrc.c:1178 [inline] io_register_clone_buffers+0x484/0xa14 io_uring/rsrc.c:1287 __io_uring_register io_uring/register.c:815 [inline] __do_sys_io_uring_register io_uring/register.c:926 [inline] __se_sys_io_uring_register io_uring/register.c:903 [inline] __arm64_sys_io_uring_register+0x42c/0xea8 io_uring/register.c:903 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 which is due to offset + buffer_count being too large. The registration code checks only the total count of buffers, but given that the indexing is an array, it should also check offset + count. That can't exceed IORING_MAX_REG_BUFFERS either, as there's no way to reach buffers beyond that limit. There's no issue with registrering a table this large, outside of the fact that it's pointless to register buffers that cannot be reached, and that it can trigger this kmalloc() warning for attempting an allocation that is too large.

References

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