Is CVE-2021-33624 in the CISA KEV catalog?

No. CVE-2021-33624 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-33624?

CVE-2021-33624 has a CVSS v3 base score of 4.7 (MEDIUM).

What is the EPSS score for CVE-2021-33624?

CVE-2021-33624 has an EPSS score of 0.92% (56th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-33624?

Upgrade linux on debian 11 to 5.10.46-1 or later. Fixes are available for 80 affected products.

CVE & CISA-KEV Catalog

CVE-2021-33624

MEDIUM

4.7

CVSS v3

NVD

Description

In kernel/bpf/verifier.c in the Linux kernel before 5.12.13, a branch can be mispredicted (e.g., because of type confusion) and consequently an unprivileged BPF program can read arbitrary memory locations via a side-channel attack, aka CID-9183671af6db.

CWE-843Type Confusion

How to fix

Remediation Available

linuxDebian

Fixed in:5.10.46-1CVE-2021-33624

linuxUbuntu

Fixed in:5.4.0-88.99USN-5091-1

linux-awsUbuntu

Fixed in:5.4.0-1057.60USN-5091-1

linux-aws-5.11Ubuntu

Fixed in:5.11.0-1019.20~20.04.1USN-5092-1

linux-aws-5.4Ubuntu

Fixed in:5.4.0-1057.60~18.04.1USN-5091-1

linux-azureUbuntu

Fixed in:5.4.0-1059.62USN-5091-1

linux-azure-5.11Ubuntu

Fixed in:5.11.0-1017.18~20.04.1USN-5092-2

linux-azure-5.4Ubuntu

Fixed in:5.4.0-1059.62~18.04.1USN-5091-1

linux-gcpUbuntu

Fixed in:5.4.0-1053.57USN-5091-1

linux-gcp-5.4Ubuntu

Fixed in:5.4.0-1053.57~18.04.1USN-5091-1

linux-gkeUbuntu

Fixed in:5.4.0-1053.56USN-5091-1

linux-gke-5.4Ubuntu

Fixed in:5.4.0-1053.56~18.04.1USN-5091-1

linux-gkeopUbuntu

Fixed in:5.4.0-1024.25USN-5091-1

linux-gkeop-5.4Ubuntu

Fixed in:5.4.0-1024.25~18.04.1USN-5091-1

linux-hwe-5.11Ubuntu

Fixed in:5.11.0-37.41~20.04.2USN-5092-2

linux-hwe-5.4Ubuntu

Fixed in:5.4.0-87.98~18.04.1USN-5091-1

linux-image-5.10.0-1050-oemUbuntu

Fixed in:5.10.0-1050.52USN-5115-1

linux-image-5.11.0-1017-azureUbuntu

Fixed in:5.11.0-1017.18~20.04.1USN-5092-2

linux-image-5.11.0-1019-awsUbuntu

Fixed in:5.11.0-1019.20~20.04.1USN-5092-1

linux-image-5.11.0-1019-oracleUbuntu

Fixed in:5.11.0-1019.20~20.04.1USN-5092-2

linux-image-5.11.0-37-genericUbuntu

Fixed in:5.11.0-37.41~20.04.2USN-5092-2

linux-image-5.11.0-37-generic-64kUbuntu

Fixed in:5.11.0-37.41~20.04.2USN-5092-2

linux-image-5.11.0-37-generic-lpaeUbuntu

Fixed in:5.11.0-37.41~20.04.2USN-5092-2

linux-image-5.11.0-37-lowlatencyUbuntu

Fixed in:5.11.0-37.41~20.04.2USN-5092-2

linux-image-5.4.0-1024-gkeopUbuntu

Fixed in:5.4.0-1024.25~18.04.1USN-5091-1

Fixed in:5.4.0-1024.25USN-5091-1

linux-image-5.4.0-1044-raspiUbuntu

Fixed in:5.4.0-1044.48~18.04.1USN-5091-2

Fixed in:5.4.0-1044.48USN-5091-2

linux-image-5.4.0-1047-kvmUbuntu

Fixed in:5.4.0-1047.49USN-5091-1

linux-image-5.4.0-1053-gcpUbuntu

Fixed in:5.4.0-1053.57~18.04.1USN-5091-1

Fixed in:5.4.0-1053.57USN-5091-1

linux-image-5.4.0-1053-gkeUbuntu

Fixed in:5.4.0-1053.56~18.04.1USN-5091-1

Fixed in:5.4.0-1053.56USN-5091-1

linux-image-5.4.0-1055-oracleUbuntu

Fixed in:5.4.0-1055.59~18.04.1USN-5091-1

Fixed in:5.4.0-1055.59USN-5091-1

linux-image-5.4.0-1057-awsUbuntu

Fixed in:5.4.0-1057.60~18.04.1USN-5091-1

Fixed in:5.4.0-1057.60USN-5091-1

linux-image-5.4.0-1059-azureUbuntu

Fixed in:5.4.0-1059.62~18.04.1USN-5091-1

Fixed in:5.4.0-1059.62USN-5091-1

linux-image-5.4.0-87-genericUbuntu

Fixed in:5.4.0-87.98~18.04.1USN-5091-1

linux-image-5.4.0-87-generic-lpaeUbuntu

Fixed in:5.4.0-87.98~18.04.1USN-5091-1

linux-image-5.4.0-87-lowlatencyUbuntu

Fixed in:5.4.0-87.98~18.04.1USN-5091-1

linux-image-5.4.0-88-genericUbuntu

Fixed in:5.4.0-88.99USN-5091-1

linux-image-5.4.0-88-generic-lpaeUbuntu

Fixed in:5.4.0-88.99USN-5091-1

linux-image-5.4.0-88-lowlatencyUbuntu

Fixed in:5.4.0-88.99USN-5091-1

linux-image-awsUbuntu

Fixed in:5.4.0.1057.40USN-5091-1

Fixed in:5.11.0.1019.20~20.04.18USN-5092-1

linux-image-aws-lts-20.04Ubuntu

Fixed in:5.4.0.1057.60USN-5091-1

linux-image-azureUbuntu

Fixed in:5.4.0.1059.39USN-5091-1

linux-image-azure-edgeUbuntu

Fixed in:5.11.0.1017.18~20.04.16USN-5092-2

linux-image-azure-lts-20.04Ubuntu

Fixed in:5.4.0.1059.57USN-5091-1

linux-image-gcpUbuntu

Fixed in:5.4.0.1053.39USN-5091-1

linux-image-gcp-lts-20.04Ubuntu

Fixed in:5.4.0.1053.63USN-5091-1

linux-image-genericUbuntu

Fixed in:5.4.0.88.92USN-5091-1

linux-image-generic-64k-hwe-20.04Ubuntu

Fixed in:5.11.0.37.41~20.04.16USN-5092-2

linux-image-generic-hwe-18.04Ubuntu

Fixed in:5.4.0.87.98~18.04.78USN-5091-1

linux-image-generic-hwe-20.04Ubuntu

Fixed in:5.11.0.37.41~20.04.16USN-5092-2

linux-image-generic-lpaeUbuntu

Fixed in:5.4.0.88.92USN-5091-1

linux-image-generic-lpae-hwe-18.04Ubuntu

Fixed in:5.4.0.87.98~18.04.78USN-5091-1

linux-image-generic-lpae-hwe-20.04Ubuntu

Fixed in:5.11.0.37.41~20.04.16USN-5092-2

linux-image-gkeUbuntu

Fixed in:5.4.0.1053.63USN-5091-1

linux-image-gke-5.4Ubuntu

Fixed in:5.4.0.1053.56~18.04.18USN-5091-1

Fixed in:5.4.0.1053.63USN-5091-1

linux-image-gkeopUbuntu

Fixed in:5.4.0.1024.27USN-5091-1

linux-image-gkeop-5.4Ubuntu

Fixed in:5.4.0.1024.25~18.04.25USN-5091-1

Fixed in:5.4.0.1024.27USN-5091-1

linux-image-kvmUbuntu

Fixed in:5.4.0.1047.46USN-5091-1

linux-image-lowlatencyUbuntu

Fixed in:5.4.0.88.92USN-5091-1

linux-image-lowlatency-hwe-18.04Ubuntu

Fixed in:5.4.0.87.98~18.04.78USN-5091-1

linux-image-lowlatency-hwe-20.04Ubuntu

Fixed in:5.11.0.37.41~20.04.16USN-5092-2

linux-image-oemUbuntu

Fixed in:5.4.0.87.98~18.04.78USN-5091-1

Fixed in:5.4.0.88.92USN-5091-1

linux-image-oem-20.04Ubuntu

Fixed in:5.10.0.1050.52USN-5115-1

linux-image-oem-20.04bUbuntu

Fixed in:5.10.0.1050.52USN-5115-1

linux-image-oem-osp1Ubuntu

Fixed in:5.4.0.87.98~18.04.78USN-5091-1

Fixed in:5.4.0.88.92USN-5091-1

linux-image-oracleUbuntu

Fixed in:5.4.0.1055.59~18.04.35USN-5091-1

Fixed in:5.11.0.1019.20~20.04.12USN-5092-2

linux-image-oracle-lts-20.04Ubuntu

Fixed in:5.4.0.1055.55USN-5091-1

linux-image-raspiUbuntu

Fixed in:5.4.0.1044.79USN-5091-2

linux-image-raspi-hwe-18.04Ubuntu

Fixed in:5.4.0.1044.47USN-5091-2

linux-image-raspi2Ubuntu

Fixed in:5.4.0.1044.79USN-5091-2

linux-image-snapdragon-hwe-18.04Ubuntu

Fixed in:5.4.0.87.98~18.04.78USN-5091-1

linux-image-virtualUbuntu

Fixed in:5.4.0.88.92USN-5091-1

linux-image-virtual-hwe-18.04Ubuntu

Fixed in:5.4.0.87.98~18.04.78USN-5091-1

linux-image-virtual-hwe-20.04Ubuntu

Fixed in:5.11.0.37.41~20.04.16USN-5092-2

linux-kvmUbuntu

Fixed in:5.4.0-1047.49USN-5091-1

linux-oem-5.10Ubuntu

Fixed in:5.10.0-1050.52USN-5115-1

linux-oracleUbuntu

Fixed in:5.4.0-1055.59USN-5091-1

linux-oracle-5.11Ubuntu

Fixed in:5.11.0-1019.20~20.04.1USN-5092-2

linux-oracle-5.4Ubuntu

Fixed in:5.4.0-1055.59~18.04.1USN-5091-1

linux-raspiUbuntu

Fixed in:5.4.0-1044.48USN-5091-2

linux-raspi-5.4Ubuntu

Fixed in:5.4.0-1044.48~18.04.1USN-5091-2

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityHigh

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

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

Exploit Intelligence

0.92%probability of exploitation in 30 days

56thpercentile

Moderate risk: more likely to be exploited than 56% of all known CVEs.

References

Patch1

github.com

Exploit1

openwall.com

Third-Party Advisory2

Other references1

github.com

Related Vulnerabilities

Other CWE-843 (Type Confusion) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2011-0611	High	8.8	99%	KEV	Fix
CVE-2012-0507	Critical	9.8	98%	KEV + Ransom	-
CVE-2017-8291	High	7.8	97%	KEV	Fix
CVE-2019-0752	High	7.5	82%	KEV + Ransom	-
CVE-2017-0037	High	8.1	80%	KEV	-
CVE-2016-7201	High	8.8	80%	KEV	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-11.