VulnerabilityPublished 30 Oct 2025Updated 31 Jul 2026

CVE-2025-40088: Linux kernel · hfsplus: fix slab-out-of-bounds read in hfsplus_strcasecmp()

Affects Linux kernelSource GCVE Database

Not known to be exploited · CVSS 7.1 High · fixed in 5.15.0-1114.123~20.04.1 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score

7.1High

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 5.15.0-1114.123~20.04.1, 5.15.0-1110.119~20.04.1, 5.15.0-1100.109~20.04.1 +2

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

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
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 30 Oct 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.

ghsa-9gj3-hmj4-wf3x

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
linux	Affected <5.15.0-1100.107~20.04.2 <5.15.0-1110.119~20.04.1 <5.15.0-1114.123~20.04.1 <5.15.0-1100.109~20.04.1 <5.15.0-170.180~20.04.3	Fixed in 5.15.0-1100.107~20.04.2 5.15.0-1110.119~20.04.1 5.15.0-1114.123~20.04.1 5.15.0-1100.109~20.04.1 5.15.0-170.180~20.04.3

AI-suggested

A fix for this vulnerability has been implemented in the Linux kernel. Users and administrators should apply the official kernel updates that include this patch to remediate the issue.

Description

In the Linux kernel, the following vulnerability has been resolved: hfsplus: fix slab-out-of-bounds read in hfsplus_strcasecmp() The hfsplus_strcasecmp() logic can trigger the issue: [ 117.317703][ T9855] ================================================================== [ 117.318353][ T9855] BUG: KASAN: slab-out-of-bounds in hfsplus_strcasecmp+0x1bc/0x490 [ 117.318991][ T9855] Read of size 2 at addr ffff88802160f40c by task repro/9855 [ 117.319577][ T9855] [ 117.319773][ T9855] CPU: 0 UID: 0 PID: 9855 Comm: repro Not tainted 6.17.0-rc6 #33 PREEMPT(full) [ 117.319780][ T9855] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 117.319783][ T9855] Call Trace: [ 117.319785][ T9855] <TASK> [ 117.319788][ T9855] dump_stack_lvl+0x1c1/0x2a0 [ 117.319795][ T9855] ? __virt_addr_valid+0x1c8/0x5c0 [ 117.319803][ T9855] ? __pfx_dump_stack_lvl+0x10/0x10 [ 117.319808][ T9855] ? rcu_is_watching+0x15/0xb0 [ 117.319816][ T9855] ? lock_release+0x4b/0x3e0 [ 117.319821][ T9855] ? __kasan_check_byte+0x12/0x40 [ 117.319828][ T9855] ? __virt_addr_valid+0x1c8/0x5c0 [ 117.319835][ T9855] ? __virt_addr_valid+0x4a5/0x5c0 [ 117.319842][ T9855] print_report+0x17e/0x7e0 [ 117.319848][ T9855] ? __virt_addr_valid+0x1c8/0x5c0 [ 117.319855][ T9855] ? __virt_addr_valid+0x4a5/0x5c0 [ 117.319862][ T9855] ? __phys_addr+0xd3/0x180 [ 117.319869][ T9855] ? hfsplus_strcasecmp+0x1bc/0x490 [ 117.319876][ T9855] kasan_report+0x147/0x180 [ 117.319882][ T9855] ? hfsplus_strcasecmp+0x1bc/0x490 [ 117.319891][ T9855] hfsplus_strcasecmp+0x1bc/0x490 [ 117.319900][ T9855] ? __pfx_hfsplus_cat_case_cmp_key+0x10/0x10 [ 117.319906][ T9855] hfs_find_rec_by_key+0xa9/0x1e0 [ 117.319913][ T9855] __hfsplus_brec_find+0x18e/0x470 [ 117.319920][ T9855] ? __pfx_hfsplus_bnode_find+0x10/0x10 [ 117.319926][ T9855] ? __pfx_hfs_find_rec_by_key+0x10/0x10 [ 117.319933][ T9855] ? __pfx___hfsplus_brec_find+0x10/0x10 [ 117.319942][ T9855] hfsplus_brec_find+0x28f/0x510 [ 117.319949][ T9855] ? __pfx_hfs_find_rec_by_key+0x10/0x10 [ 117.319956][ T9855] ? __pfx_hfsplus_brec_find+0x10/0x10 [ 117.319963][ T9855] ? __kmalloc_noprof+0x2a9/0x510 [ 117.319969][ T9855] ? hfsplus_find_init+0x8c/0x1d0 [ 117.319976][ T9855] hfsplus_brec_read+0x2b/0x120 [ 117.319983][ T9855] hfsplus_lookup+0x2aa/0x890 [ 117.319990][ T9855] ? __pfx_hfsplus_lookup+0x10/0x10 [ 117.320003][ T9855] ? d_alloc_parallel+0x2f0/0x15e0 [ 117.320008][ T9855] ? __lock_acquire+0xaec/0xd80 [ 117.320013][ T9855] ? __pfx_d_alloc_parallel+0x10/0x10 [ 117.320019][ T9855] ? __raw_spin_lock_init+0x45/0x100 [ 117.320026][ T9855] ? __init_waitqueue_head+0xa9/0x150 [ 117.320034][ T9855] __lookup_slow+0x297/0x3d0 [ 117.320039][ T9855] ? __pfx___lookup_slow+0x10/0x10 [ 117.320045][ T9855] ? down_read+0x1ad/0x2e0 [ 117.320055][ T9855] lookup_slow+0x53/0x70 [ 117.320065][ T9855] walk_component+0x2f0/0x430 [ 117.320073][ T9855] path_lookupat+0x169/0x440 [ 117.320081][ T9855] filename_lookup+0x212/0x590 [ 117.320089][ T9855] ? __pfx_filename_lookup+0x10/0x10 [ 117.320098][ T9855] ? strncpy_from_user+0x150/0x290 [ 117.320105][ T9855] ? getname_flags+0x1e5/0x540 [ 117.320112][ T9855] user_path_at+0x3a/0x60 [ 117.320117][ T9855] __x64_sys_umount+0xee/0x160 [ 117.320123][ T9855] ? __pfx___x64_sys_umount+0x10/0x10 [ 117.320129][ T9855] ? do_syscall_64+0xb7/0x3a0 [ 117.320135][ T9855] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 117.320141][ T9855] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 117.320145][ T9855] do_syscall_64+0xf3/0x3a0 [ 117.320150][ T9855] ? exc_page_fault+0x9f/0xf0 [ 117.320154][ T9855] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 117.320158][ T9855] RIP: 0033:0x7f7dd7908b07 [ 117.320163][ T9855] Code: 23 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 08 [ 117.320167][ T9855] RSP: 002b:00007ffd5ebd9698 EFLAGS: 00000202 ---truncated---

Impact

Successful exploitation of this vulnerability could result in a high impact, including disclosure of kernel memory contents (confidentiality impact) and denial of service due to kernel crashes (availability impact). Integrity impact is not indicated. The CVSS vector specifies local attack vector with low complexity and low privileges required, no user interaction, and unchanged scope.

Summary

The Linux kernel contained a vulnerability in the hfsplus filesystem implementation where the hfsplus_strcasecmp() function could perform a slab-out-of-bounds read. This was detected by KASAN during kernel runtime, indicating a memory safety violation. The vulnerability was resolved in a kernel update, preventing out-of-bounds memory access in the string comparison logic used by the HFS+ filesystem driver.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Jul 2026, 16:24 UTC

Technical details

References

Community reviews

Related threats