CVE-2021-47312

netfilter: nf_tables: Fix dereference of null pointer flow

MEDIUM
5.5
CVSS Score
Published: May 21, 2024 at 02:35 PM UTC
Updated: June 17, 2026 at 04:17 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: Fix dereference of null pointer flow In the case where chain->flags & NFT_CHAIN_HW_OFFLOAD is false then nft_flow_rule_create is not called and flow is NULL. The subsequent error handling execution via label err_destroy_flow_rule will lead to a null pointer dereference on flow when calling nft_flow_rule_destroy. Since the error path to err_destroy_flow_rule has to cater for null and non-null flows, only call nft_flow_rule_destroy if flow is non-null to fix this issue. Addresses-Coverity: ("Explicity null dereference")

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.13.2 ≤ v < 5.13.53c5e44622011b9ea21bd425875dcccfc9a158f5f5.13.29b1f676e2e0bbff67c568672c565c6f31470157
Vendor states this is fixed in 4ca041f919f13783b0b03894783deee00dbca19a (fixed)
Vendor states this is fixed in 70a5a1950cca02c5cd161bb3846b4d983eed97d3 (fixed)
Affected range stops below 5.13.5, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/4ca041f919f13783b0b03894783deee00dbca19a
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/70a5a1950cca02c5cd161bb3846b4d983eed97d3

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.5MEDIUMCISA-ADP
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-476

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