Linux Kernel up to 7.1.2/7.2 Nfsd nfsd4_create cr_dpacl/cr_pacl memory leak

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.1.2/7.2 and classified as critical. Impacted is the function nfsd4_create of the component Nfsd. Such manipulation of the argument cr_dpacl/cr_pacl leads to memory leak. This vulnerability is uniquely identified as CVE-2026-53395. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.1.2/7.2. It has been rated as critical. Affected by this issue is the function nfsd4_create of the component Nfsd. The manipulation of the argument cr_dpacl/cr_pacl with an unknown input leads to a memory leak vulnerability. Using CWE to declare the problem leads to CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. Impacted is availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix dead ACL conflict guard in nfsd4_create nfsd4_create() steals create->cr_dpacl/cr_pacl into the local nfsd_attrs via the designated initializer, then immediately sets the source pointers to NULL. The subsequent conflict guard tests the already-nilled source fields, making it permanently dead code: if (create->cr_acl) { if (create->cr_dpacl || create->cr_pacl) /* always false */ When a client encodes both FATTR4_WORD0_ACL and FATTR4_WORD2_POSIX_{DEFAULT,ACCESS}_ACL in the same CREATE fattr bitmap, nfsd4_acl_to_attr() overwrites attrs.na_pacl/na_dpacl without releasing the originals, leaking two posix_acl slab objects per request. Repeated requests cause unbounded slab exhaustion. Fix by checking attrs.na_dpacl/na_pacl (the stolen values) instead of the nilled create->cr_dpacl/cr_pacl, matching the correct pattern already used in nfsd4_setattr().

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-53395 since 06/09/2026. The exploitation is known to be easy. The attack may be launched remotely. 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 07/19/2026). The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 7.1.3 or 7.2-rc1 eliminates this vulnerability.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.0
• 7.1
• 7.1.0
• 7.1.1
• 7.1.2
• 7.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

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