Linux Kernel up to 7.2.5 NFSv4.2 encode_layoutstats buffer overflow

CVSS Meta Temp Score
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CTI Interest Score
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6.2$0-$5k0.40+

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2.5. It has been classified as critical. This vulnerability affects the function encode_layoutstats of the component NFSv4.2. The manipulation leads to buffer overflow. This vulnerability is uniquely identified as CVE-2026-90103. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2.5 and classified as critical. This issue affects the function encode_layoutstats of the component NFSv4.2. The manipulation with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: NFSv4.2: fix LAYOUTSTATS send buffer exhaustion encode_layoutstats_maxsz budgets XDR_QUADLEN(PNFS_LAYOUTSTATS_MAXSIZE), i.e. 256 bytes, for the layoutupdate4 body written by the layout driver. The flexfiles record can exceed that. ff_layout_encode_ff_layoutupdate() emits, per data server, a netaddr4, an nfs_fh4, two ff_io_latency4, an nfstime4 and a bool. A data server whose filehandle is NFS_MAXFHSIZE bytes long already accounts for 132 of those bytes, and the two ff_io_latency4 at 64 bytes each, the nfstime4 and the bool add a further 144, so the body passes 256 bytes before the netaddr4 is encoded at all. encode_layoutstats() additionally writes the deviceid4 and the layoutupdate4 lou_type word, neither of which the macro accounts for. The filehandle and the address are both chosen by the server, through LAYOUTGET and GETDEVICEINFO, so it can drive the encoder past the end of the send buffer. xdr_reserve_space() returns NULL once that happens, and the two ff_layout_encode_io_latency() calls run with dss_info->mirror->lock held, so a NULL return there leaves the lock permanently held. Raise PNFS_LAYOUTSTATS_MAXSIZE to 384 so that the record fits inside the reservation.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-90103 since 09/11/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/17/2026).

Upgrading to version 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch 842ac26615424577f24f0486b9d3bf97f28fad9c/397aa7000bbf6b6a0d32e66a544e978fb478c8e4/e82d7d999fe9f893f84bf332fd39cb5d9de7128f/5aca000630c0fd0da102ae1abf9245dd74f2ce36/cb11590c7ddc6883a1b1d70b1f98b2779fe626f2/3815b894b922e9b4f40b8b6f6d67bf80d44141c9/a973622da0c62c34043ddbbf382cd761b03e5136/c75ef2137e749f2673f0617cfdaae53b2bb7195a is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.5
VulDB Meta Temp Score: 6.2

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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 5.10.270/5.15.221/6.1.188/6.6.157/6.12.110/6.18.52/7.2.6/7.3-rc1
Patch: 842ac26615424577f24f0486b9d3bf97f28fad9c/397aa7000bbf6b6a0d32e66a544e978fb478c8e4/e82d7d999fe9f893f84bf332fd39cb5d9de7128f/5aca000630c0fd0da102ae1abf9245dd74f2ce36/cb11590c7ddc6883a1b1d70b1f98b2779fe626f2/3815b894b922e9b4f40b8b6f6d67bf80d44141c9/a973622da0c62c34043ddbbf382cd761b03e5136/c75ef2137e749f2673f0617cfdaae53b2bb7195a

Timelineinfo

09/11/2026 CVE reserved
09/17/2026 +6 days Advisory disclosed
09/17/2026 +0 days VulDB entry created
09/17/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-90103 (🔒)
GCVE (CVE): GCVE-0-2026-90103
GCVE (VulDB): GCVE-100-406607

Entryinfo

Created: 09/17/2026 19:17
Changes: 09/17/2026 19:17 (59)
Complete: 🔍
Cache ID: 216::103

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