CVE-2021-47316
Linux NFSd NULL Pointer Dereference Vulnerability
Description
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix NULL dereference in nfs3svc_encode_getaclres In error cases the dentry may be NULL. Before 20798dfe249a, the encoder also checked dentry and d_really_is_positive(dentry), but that looks like overkill to me--zero status should be enough to guarantee a positive dentry. This isn't the first time we've seen an error-case NULL dereference hidden in the initialization of a local variable in an xdr encoder. But I went back through the other recent rewrites and didn't spot any similar bugs.
INFO
Published Date :
May 21, 2024, 3:15 p.m.
Last Modified :
Dec. 24, 2024, 4:28 p.m.
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Remotely Exploitable :
No
Impact Score :
3.6
Exploitability Score :
1.8
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-47316.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-47316 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-47316 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
Dec. 24, 2024
Action Type Old Value New Value Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE NIST CWE-476 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.13 up to (excluding) 5.13.4 Changed Reference Type https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870 No Types Assigned https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870 Patch Changed Reference Type https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870 No Types Assigned https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870 Patch Changed Reference Type https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8 No Types Assigned https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8 Patch Changed Reference Type https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8 No Types Assigned https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8 Patch Changed Reference Type https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d No Types Assigned https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d Patch Changed Reference Type https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d No Types Assigned https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d Patch -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870 Added Reference https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8 Added Reference https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jun. 21, 2024
Action Type Old Value New Value Added Reference kernel.org https://git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d [No types assigned] -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 28, 2024
Action Type Old Value New Value -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 21, 2024
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: nfsd: fix NULL dereference in nfs3svc_encode_getaclres In error cases the dentry may be NULL. Before 20798dfe249a, the encoder also checked dentry and d_really_is_positive(dentry), but that looks like overkill to me--zero status should be enough to guarantee a positive dentry. This isn't the first time we've seen an error-case NULL dereference hidden in the initialization of a local variable in an xdr encoder. But I went back through the other recent rewrites and didn't spot any similar bugs. Added Reference kernel.org https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8 [No types assigned]
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-47316 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-47316
weaknesses.