NULL pointer dereference in Linux

CVE-2021-47316

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.006 (47.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 47.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2021-47316: held from 0.006 to 0.006.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

  • Linux — versions d505e66191072748620fc0af038cea4e4da0e3cd, 20798dfe249a01ad1b12eec7dbc572db5003244a, 5.13
  • Linux Kernel

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-47316?
CVE-2021-47316 is a high-severity vulnerability in Linux, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2024-05-21.
How severe is CVE-2021-47316?
High severity. CVSS v3 base score is 7.5 out of 10.