Linux Kernel up to 6.6.159/6.12.113/6.18.56/7.2.10 Mount Namespace path_pivot_root use after free

CVSS Meta Temp Score
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CTI Interest Score
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7.8$0-$5k1.19

Summaryinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 6.6.159/6.12.113/6.18.56/7.2.10. This affects the function path_pivot_root of the component Mount Namespace. Executing a manipulation can lead to use after free. This vulnerability is tracked as CVE-2026-98985. The attack is restricted to local execution. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.6.159/6.12.113/6.18.56/7.2.10 and classified as very critical. This vulnerability affects the function path_pivot_root of the component Mount Namespace. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: namespace: check the mounts before reading their parents in pivot_root() path_pivot_root() reads the parents of new_root and of the caller's root and checks whether they are shared before it checks that either mount is in the caller's mount namespace. Only namespace_sem is held. That's fine for a mount that is in the caller's mount namespace. But new_root can be a file descriptor to a mount that has been unmounted and that only the file descriptor keeps alive. If that mount stayed attached to its parent when it was unmounted nothing pins the parent for it. The final mntput() of the parent unhooks the children under mount_lock alone and frees the parent afterwards: pivot_root() close(fd), last ref on the parent ------------ --------------------------------- ex_parent = new_mnt->mnt_parent mntput_no_expire_slowpath() __umount_mnt(new_mnt) cleanup_mnt() call_rcu() IS_MNT_SHARED(ex_parent) BUG: KASAN: slab-use-after-free in path_pivot_root+0xf1a/0x1840 Read of size 4 at addr ffff8881047382f8 by task pivot_widen/157 path_pivot_root+0xf1a/0x1840 __x64_sys_pivot_root+0x165/0x190 The same goes for the caller's root via chroot(). Both outcomes of the check end in EINVAL so nothing but the read itself goes wrong. It's the same thing commit bb4609405752 ("statmount: read the parent of an unmounted mount under mount_lock") fixed for statmount(). Check that both mounts are in the caller's namespace before their parents are read. Every path returns EINVAL either way.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-98985 since 09/25/2026. The exploitation appears to be easy. The attack needs to be approached locally. Additional levels of successful authentication are required for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/23/2026).

Upgrading to version 6.6.160, 6.12.114, 6.18.57 or 7.2.11 eliminates this vulnerability. Applying the patch a56d4f8f8f4c5d9ac339d5c03a9d90eecd3697fc/3c2441e21c3df867e4131e0ff784ecdb3a7a55f8/e3aba6900483f64e6c9eb328150dd633b7d36c1c/3dad2330c89343ba083cf7868779083fd5fbe0fe/6b7c001eb5857fa09041f47673666060a2e5fc1c is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.2
VulDB Meta Temp Score: 7.8

VulDB Base Score: 8.2
VulDB Temp Score: 7.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.160/6.12.114/6.18.57/7.2.11
Patch: a56d4f8f8f4c5d9ac339d5c03a9d90eecd3697fc/3c2441e21c3df867e4131e0ff784ecdb3a7a55f8/e3aba6900483f64e6c9eb328150dd633b7d36c1c/3dad2330c89343ba083cf7868779083fd5fbe0fe/6b7c001eb5857fa09041f47673666060a2e5fc1c

Timelineinfo

09/25/2026 CVE reserved
10/23/2026 +28 days Advisory disclosed
10/23/2026 +0 days VulDB entry created
10/23/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98985 (🔒)
GCVE (CVE): GCVE-0-2026-98985
GCVE (VulDB): GCVE-100-425812

Entryinfo

Created: 10/23/2026 15:31
Changes: 10/23/2026 15:31 (59)
Complete: 🔍
Cache ID: 216::103

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