VulnerabilityPublished 18 Jun 2025Updated 31 Jul 2026

CVE-2025-38050: Linux kernel · mm/hugetlb: fix kernel NULL pointer dereference when replacing free hugetlb folios

Affects Linux kernelSource GCVE Database

Not known to be exploited · CVSS 5.5 Medium · fixed in 6.14.0-1013.13~24.04.1 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 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 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 6.14.0-1013.13~24.04.1, 6.14.0-1007.7, 6.14.0-1016.17~24.04.1 +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 18 Jun 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 <6.14.0-1013.13~24.04.1	Fixed in 6.14.0-1013.13~24.04.1
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-6.14`pkg:deb/ubuntu/linux-gcp-6.14?arch=source&distro=noble`Other threats	Affected <6.14.0-1016.17~24.04.1	Fixed in 6.14.0-1016.17~24.04.1
Ubuntu 24.04 LTSlinux-oem-6.14`pkg:deb/ubuntu/linux-oem-6.14?arch=source&distro=noble`Other threats	Affected <6.14.0-1012.12	Fixed in 6.14.0-1012.12
Ubuntu 24.04 LTSlinux-oracle-6.14`pkg:deb/ubuntu/linux-oracle-6.14?arch=source&distro=noble`Other threats	Affected <6.14.0-1013.13~24.04.1	Fixed in 6.14.0-1013.13~24.04.1

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: mm/hugetlb: fix kernel NULL pointer dereference when replacing free hugetlb folios A kernel crash was observed when replacing free hugetlb folios: BUG: kernel NULL pointer dereference, address: 0000000000000028 PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 28 UID: 0 PID: 29639 Comm: test_cma.sh Tainted 6.15.0-rc6-zp #41 PREEMPT(voluntary) RIP: 0010:alloc_and_dissolve_hugetlb_folio+0x1d/0x1f0 RSP: 0018:ffffc9000b30fa90 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000342cca RCX: ffffea0043000000 RDX: ffffc9000b30fb08 RSI: ffffea0043000000 RDI: 0000000000000000 RBP: ffffc9000b30fb20 R08: 0000000000001000 R09: 0000000000000000 R10: ffff88886f92eb00 R11: 0000000000000000 R12: ffffea0043000000 R13: 0000000000000000 R14: 00000000010c0200 R15: 0000000000000004 FS: 00007fcda5f14740(0000) GS:ffff8888ec1d8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000028 CR3: 0000000391402000 CR4: 0000000000350ef0 Call Trace: <TASK> replace_free_hugepage_folios+0xb6/0x100 alloc_contig_range_noprof+0x18a/0x590 ? srso_return_thunk+0x5/0x5f ? down_read+0x12/0xa0 ? srso_return_thunk+0x5/0x5f cma_range_alloc.constprop.0+0x131/0x290 __cma_alloc+0xcf/0x2c0 cma_alloc_write+0x43/0xb0 simple_attr_write_xsigned.constprop.0.isra.0+0xb2/0x110 debugfs_attr_write+0x46/0x70 full_proxy_write+0x62/0xa0 vfs_write+0xf8/0x420 ? srso_return_thunk+0x5/0x5f ? filp_flush+0x86/0xa0 ? srso_return_thunk+0x5/0x5f ? filp_close+0x1f/0x30 ? srso_return_thunk+0x5/0x5f ? do_dup2+0xaf/0x160 ? srso_return_thunk+0x5/0x5f ksys_write+0x65/0xe0 do_syscall_64+0x64/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e There is a potential race between __update_and_free_hugetlb_folio() and replace_free_hugepage_folios(): CPU1 CPU2 __update_and_free_hugetlb_folio replace_free_hugepage_folios folio_test_hugetlb(folio) -- It's still hugetlb folio. __folio_clear_hugetlb(folio) hugetlb_free_folio(folio) h = folio_hstate(folio) -- Here, h is NULL pointer When the above race condition occurs, folio_hstate(folio) returns NULL, and subsequent access to this NULL pointer will cause the system to crash. To resolve this issue, execute folio_hstate(folio) under the protection of the hugetlb_lock lock, ensuring that folio_hstate(folio) does not return NULL.

References

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