FreeBSD Kernel up to p0.x/p6/p10/p15 Path Resolution unlinkat/funlinkat AT_RESOLVE_BENEATH access control

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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8.4$0-$5k3.44-

Summaryinfo

A vulnerability was found in FreeBSD Kernel up to p0.x/p6/p10/p15. It has been declared as very critical. Affected is the function unlinkat/funlinkat of the component Path Resolution. Such manipulation of the argument AT_RESOLVE_BENEATH leads to access control. This vulnerability is referenced as CVE-2026-49421. The attack can only be performed from a local environment. No exploit is available.

Detailsinfo

A vulnerability was found in FreeBSD Kernel up to p0.x/p6/p10/p15. It has been rated as very critical. Affected by this issue is the function unlinkat/funlinkat of the component Path Resolution. The manipulation of the argument AT_RESOLVE_BENEATH with an unknown input leads to a access control vulnerability. Using CWE to declare the problem leads to CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. Impacted is confidentiality, integrity, and availability. CVE summarizes:

The kernel function that implements unlinkat(2) and funlinkat(2) validated the AT_RESOLVE_BENEATH flag but failed to pass it through to the underlying path lookup. The flag was silently dropped, so path resolution was not actually restricted. A process that uses AT_RESOLVE_BENEATH with unlinkat(2) or funlinkat(2) to confine path resolution can in fact resolve paths above the starting directory. A caller relying on this flag for path containment may delete files outside the intended directory tree.

The advisory is available at security.freebsd.org. This vulnerability is handled as CVE-2026-49421 since 05/29/2026. The exploitation is known to be easy. Local access is required to approach this attack. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 08/19/2026). This vulnerability is assigned to T1068 by the MITRE ATT&CK project.

Upgrading to version p1, p7, p11 or p16 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.4

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
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: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

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 p1/p7/p11/p16

Timelineinfo

05/29/2026 CVE reserved
08/19/2026 +82 days Advisory disclosed
08/19/2026 +0 days VulDB entry created
08/19/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: security.freebsd.org
Status: Confirmed

CVE: CVE-2026-49421 (🔒)
GCVE (CVE): GCVE-0-2026-49421
GCVE (VulDB): GCVE-100-392930

Entryinfo

Created: 08/19/2026 07:45
Changes: 08/19/2026 07:45 (57)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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