Linux Kernel up to 7.1.7/7.2-rc5 netfs fs/netfs/write_issue.c netfs_writepages allocation of resources

Summaryinfo

A vulnerability identified as critical has been detected in Linux Kernel up to 7.1.7/7.2-rc5. Affected by this issue is the function netfs_writepages of the file fs/netfs/write_issue.c of the component netfs. The manipulation leads to allocation of resources. This vulnerability is referenced as CVE-2026-74542. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.1.7/7.2-rc5 and classified as critical. This issue affects the function netfs_writepages of the file fs/netfs/write_issue.c of the component netfs. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix folio_queue ENOMEM in writeback by adding a mempool Fix the handling of folio_queue allocation failure in writeback by adding a mempool and passing in gfp_t flags to the rolling buffer functions that allocate memory, using the mempool if gfp != GFP_KERNEL. This is then extended upwards and the gfp to be used for a request is stored in the netfs_io_request struct and is then used for both requests and subrequests, eliminating the sleeping loops there. The failure caused: folio != NULL WARNING: fs/netfs/write_issue.c:603 at netfs_writepages+0x883/0xa10 fs/netfs/write_issue.c:603, CPU#3: syz.0.17/5919

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-74542 since 08/15/2026. 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 08/15/2026). The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 7.1.8 or 7.2-rc6 eliminates this vulnerability. Applying the patch 3f6d7f8a5416d852648d15a05e895f1195ee8a85/1d78d56c43ef3768183e8370e7367b162700e049 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4
• 7.1.5
• 7.1.6
• 7.1.7
• 7.2-rc1
• 7.2-rc2
• 7.2-rc3
• 7.2-rc4
• 7.2-rc5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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