CVE-2021-47316

medium

Published 2024-05-21 · Modified 2026-05-12

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CVSS v3

5.5

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS v4 NEW

—

not yet in upstream

VIR risk

5.5

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.

Predictions

Exploit likelihood

55%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

OS impact

Linux kernel Affected 1 release

Version	Status	Fixed in
—	Affected	`5.13.4`

SUSE Affected 1 release

Version	Status	Fixed in
—	Affected	—

Debian Fixed 5 releases

Version	Status	Fixed in
trixie	Fixed	`0`
sid	Fixed	`0`
forky	Fixed	`0`
bullseye	Fixed	`0`
bookworm	Fixed	`0`

References

CWEs

CWE-476

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.