CVE-2021-33624: debian debian_linux

Modified

AliasesUBUNTU-CVE-2021-33624DEBIAN-CVE-2021-33624

Published 23-06-2021Last modified 08-10-2026

Vulnerability summary

CVE-2021-33624 is a medium (CVSS 4.7) vulnerability in debian debian_linux. EPSS estimates a 0.93% chance of exploitation in the next 30 days, higher than 60.6% of scored vulnerabilities. 1 public exploit is recorded.

Priority

Routine

Not severe (CVSS 4.7, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?

CVSS score

4.7/10

010

Medium · v3.1 (NVD)

EPSS score

0.93%

0%100%

Low · +0.01 pp in 30 days

KEVNot listedNot listed by any tracked catalog.

RansomwareNot flaggedNo ransomware use recorded.

Public exploits1reference

Timeline

23-06-2021
PublishedVulnerability first disclosed.
08-10-2026
Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 3 sources · 2 versions

v3.14.7v2.04.7

EPSS trend

Probability

0.93%

Chance of exploitation in the next 30 days

Percentile

61%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.92% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs

CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found

referenceUnverified
Exploit Reference (openwall.com)
Maturity: unknown

Weaknesses

CWE · root cause

CWE-843Access of Resource Using Incompatible TypeThe product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu58 products

linuxAll versions (No fix recorded) | < 5.4.0-88.99
linux-awsAll versions (No fix recorded) | < 5.4.0-1057.60
linux-aws-5.0All versions (No fix recorded)
linux-aws-5.11< 5.11.0-1019.20~20.04.1
linux-aws-5.3All versions (No fix recorded)

linux-aws-5.4< 5.4.0-1057.60~18.04.1
linux-aws-5.8All versions (No fix recorded)
linux-aws-fipsAll versions (No fix recorded) | < 5.4.0-1069.73+fips2
linux-aws-hweAll versions (No fix recorded)
linux-azureAll versions (No fix recorded) | < 5.4.0-1059.62
linux-azure-4.15All versions (No fix recorded)
linux-azure-5.11< 5.11.0-1017.18~20.04.1
linux-azure-5.3All versions (No fix recorded)
linux-azure-5.4< 5.4.0-1059.62~18.04.1
linux-azure-5.8All versions (No fix recorded)
linux-azure-edgeAll versions (No fix recorded)
linux-azure-fipsAll versions (No fix recorded) | < 5.4.0-1073.76+fips1
linux-bluefield< 5.4.0-1019.22
linux-fipsAll versions (No fix recorded) | < 5.4.0-1034.40
linux-gcpAll versions (No fix recorded) | < 5.4.0-1053.57
linux-gcp-4.15All versions (No fix recorded)
linux-gcp-5.11< 5.11.0-1020.22~20.04.1
linux-gcp-5.3All versions (No fix recorded)
linux-gcp-5.4< 5.4.0-1053.57~18.04.1
linux-gcp-5.8All versions (No fix recorded)
linux-gcp-edgeAll versions (No fix recorded)
linux-gcp-fipsAll versions (No fix recorded) | < 5.4.0-1067.71~20.04.1
linux-gke< 5.4.0-1053.56
linux-gke-4.15All versions (No fix recorded)
linux-gke-5.4< 5.4.0-1053.56~18.04.1
linux-gkeop< 5.4.0-1024.25
linux-gkeop-5.4< 5.4.0-1024.25~18.04.1
linux-hweAll versions (No fix recorded)
linux-hwe-5.11< 5.11.0-37.41~20.04.2
linux-hwe-5.4< 5.4.0-87.98~18.04.1
linux-hwe-5.8All versions (No fix recorded)
linux-hwe-edgeAll versions (No fix recorded)
linux-ibm< 5.4.0-1005.6
linux-intel-iot-realtimeAll versions (No fix recorded)
linux-kvmAll versions (No fix recorded) | < 5.4.0-1047.49
linux-lts-xenialAll versions (No fix recorded)
linux-oemAll versions (No fix recorded)
linux-oem-5.10< 5.10.0-1050.52
linux-oem-5.6All versions (No fix recorded)
linux-oracleAll versions (No fix recorded) | < 5.4.0-1055.59
linux-oracle-5.0All versions (No fix recorded)
linux-oracle-5.11< 5.11.0-1019.20~20.04.1
linux-oracle-5.3All versions (No fix recorded)
linux-oracle-5.4< 5.4.0-1055.59~18.04.1
linux-oracle-5.8All versions (No fix recorded)
linux-raspi< 5.4.0-1044.48
linux-raspi-5.4< 5.4.0-1044.48~18.04.1
linux-raspi-realtimeAll versions (No fix recorded)
linux-raspi2All versions (No fix recorded)
linux-realtimeAll versions (No fix recorded)
linux-riscvAll versions (No fix recorded)
linux-riscv-5.11< 5.11.0-1020.21~20.04.1
linux-riscv-5.8All versions (No fix recorded)

Show all 58

Debian2 products

linux< 5.10.46-1
debian_linuxEOL9.0

Linux1 product

linux_kernel< 5.12.13

3 vendors · 61 products

References

19 links

www.usenix.org/conference/usenixsecurity21/presentation/kirznerThird Party Advisory
www.openwall.com/lists/oss-security/2021/06/21/1ExploitMailing ListThird Party Advisory
github.com/torvalds/linux/commit/9183671af6dbf60a1219371d4ed73e23f43b49dbPatchThird Party Advisory
lists.debian.org/debian-lts-announce/2021/10/msg00010.htmlMailing ListIssue TrackingThird Party Advisory
github.com/benschlueter/CVE-2021-33624
ubuntu.com/security/CVE-2021-33624REPORT
www.openwall.com/lists/oss-security/2021/06/21/1REPORT
git.kernel.org/pub/…REPORT
git.kernel.org/pub/…REPORT
git.kernel.org/pub/…REPORT

Show all 19 references

git.kernel.org/pub/…REPORT
ubuntu.com/security/notices/USN-5091-1Advisory
ubuntu.com/security/notices/USN-5092-1Advisory
ubuntu.com/security/notices/USN-5092-2Advisory
ubuntu.com/security/notices/USN-5091-2Advisory
ubuntu.com/security/notices/USN-5115-1Advisory
www.cve.org/CVERecord?id=CVE-2021-33624REPORT
security-tracker.debian.org/tracker/CVE-2021-33624Advisory
nvd.nist.gov/vuln/detail/CVE-2021-33624OvalAdvisory