Linux Kernel up to 6.1.21/6.2.8 nfsd nfsd_splice_actor information disclosure

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.21/6.2.8. It has been rated as problematic. This issue affects the function nfsd_splice_actor of the component nfsd. The manipulation leads to information disclosure. This vulnerability is listed as CVE-2023-53083. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.1.21/6.2.8. It has been rated as problematic. This issue affects the function nfsd_splice_actor of the component nfsd. The manipulation with an unknown input leads to a information disclosure vulnerability. Using CWE to declare the problem leads to CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Impacted is confidentiality. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: nfsd: don't replace page in rq_pages if it's a continuation of last page The splice read calls nfsd_splice_actor to put the pages containing file data into the svc_rqst->rq_pages array. It's possible however to get a splice result that only has a partial page at the end, if (e.g.) the filesystem hands back a short read that doesn't cover the whole page. nfsd_splice_actor will plop the partial page into its rq_pages array and return. Then later, when nfsd_splice_actor is called again, the remainder of the page may end up being filled out. At this point, nfsd_splice_actor will put the page into the array _again_ corrupting the reply. If this is done enough times, rq_next_page will overrun the array and corrupt the trailing fields -- the rq_respages and rq_next_page pointers themselves. If we've already added the page to the array in the last pass, don't add it to the array a second time when dealing with a splice continuation. This was originally handled properly in nfsd_splice_actor, but commit 91e23b1c3982 ("NFSD: Clean up nfsd_splice_actor()") removed the check for it.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2023-53083 since 05/02/2025. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 241778 (Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2025-1054)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.22 or 6.2.9 eliminates this vulnerability. Applying the patch 8235cd619db6e67f1d7d26c55f1f3e4e575c947d/12eca509234acb6b666802edf77408bb70d7bfca/51ddb84baff6f09ad62b5999ece3ec172e4e3568/0101067f376eb7b9afd00279270f25d5111a091d/27c934dd8832dd40fd34776f916dc201e18b319b is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (241778). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4
• 6.1.5
• 6.1.6
• 6.1.7
• 6.1.8
• 6.1.9
• 6.1.10
• 6.1.11
• 6.1.12
• 6.1.13
• 6.1.14
• 6.1.15
• 6.1.16
• 6.1.17
• 6.1.18
• 6.1.19
• 6.1.20
• 6.1.21
• 6.2.0
• 6.2.1
• 6.2.2
• 6.2.3
• 6.2.4
• 6.2.5
• 6.2.6
• 6.2.7
• 6.2.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

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