CVE-2021-33034: debian debian_linux Use After Free

Analyzed

AliasesRHSA-2021:2563RHSA-2021:2668UBUNTU-CVE-2021-33034+1 more

Published 14-05-2021Last modified 03-08-2024

Vulnerability summary

CVE-2021-33034 is a high (CVSS 7.8) Use After Free vulnerability in debian debian_linux. EPSS estimates a 0.83% chance of exploitation in the next 30 days, higher than 57.4% of scored vulnerabilities. 2 public exploits are recorded.

Priority

Prioritisepublic exploit

Public exploit (reference, Date unknown)

Source freshness unavailable

How is this decided?

CVSS score

7.8/10

010

High · v3.1 (NVD)

EPSS score

0.83%

0%100%

Low · +0.01 pp in 30 days

KEVNot listedNot listed by any tracked catalog.

RansomwareNot flaggedNo ransomware use recorded.

Public exploits2reference

Advisory lineage

Upstream 0 · Downstream 57 · Related 35

DLA-2689-1 DLA-2690-1 MGASA-2021-0214 MGASA-2021-0215 OPENSUSE-SU-2021:0843-1 OPENSUSE-SU-2021:0947-1+51 more

Timeline

14-05-2021
PublishedVulnerability first disclosed.
03-08-2024
Last modifiedVulnerability information updated.

Description

In the Linux kernel before 5.12.4, net/bluetooth/hci_event.c has a use-after-free when destroying an hci_chan, aka CID-5c4c8c954409. This leads to writing an arbitrary value.

CVSS metrics

5 scores · 4 sources · 2 versions

v3.17.8v2.04.6

EPSS trend

Probability

0.83%

Chance of exploitation in the next 30 days

Percentile

57%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.82% 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

2 found

referenceUnverified
Exploit Reference (syzkaller.appspot.com)
Maturity: unknown
referenceUnverified
Exploit Reference (sites.google.com)
Maturity: unknown

Weaknesses

CWE · root cause

CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Affected systems

Version check

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

Ubuntu54 products

linuxAll versions (No fix recorded) | < 4.4.0-219.252 | < 4.15.0-151.157 | < 5.4.0-77.86
linux-aws< 4.4.0-1099.104 | < 4.4.0-1135.149 | < 4.15.0-1109.116 | < 5.4.0-1051.53
linux-aws-5.0All versions (No fix recorded)
linux-aws-5.3All versions (No fix recorded)
linux-aws-5.4< 5.4.0-1051.53~18.04.1

linux-aws-5.8< 5.8.0-1041.43~20.04.1
linux-aws-fips< 4.15.0-2051.53 | All versions (No fix recorded) | < 5.4.0-1069.73+fips2
linux-aws-hwe< 4.15.0-1109.116~16.04.1
linux-azure< 4.15.0-1121.134~14.04.1 | < 4.15.0-1121.134~16.04.1 | All versions (No fix recorded) | < 5.4.0-1051.53
linux-azure-4.15< 4.15.0-1121.134
linux-azure-5.3All versions (No fix recorded)
linux-azure-5.4< 5.4.0-1051.53~18.04.1
linux-azure-5.8< 5.8.0-1039.42~20.04.1
linux-azure-edgeAll versions (No fix recorded)
linux-azure-fde-5.15< 5.15.0-1114.123~20.04.1
linux-azure-fips< 4.15.0-2033.37 | All versions (No fix recorded) | < 5.4.0-1073.76+fips1
linux-bluefield< 5.4.0-1013.16
linux-dell300x< 4.15.0-1027.32
linux-fips< 4.4.0-1069.75 | All versions (No fix recorded) | < 4.15.0-1066.75 | < 5.4.0-1028.32
linux-gcp< 4.15.0-1106.120~16.04.1 | All versions (No fix recorded) | < 5.4.0-1046.49
linux-gcp-4.15< 4.15.0-1106.120
linux-gcp-5.3All versions (No fix recorded)
linux-gcp-5.4< 5.4.0-1046.49~18.04.1
linux-gcp-5.8< 5.8.0-1038.40~20.04.1
linux-gcp-edgeAll versions (No fix recorded)
linux-gcp-fips< 4.15.0-2016.18 | All versions (No fix recorded) | < 5.4.0-1067.71~20.04.1
linux-gke< 5.4.0-1046.48
linux-gke-4.15All versions (No fix recorded)
linux-gke-5.4< 5.4.0-1046.48~18.04.1
linux-gkeop< 5.4.0-1018.19
linux-gkeop-5.4< 5.4.0-1018.19~18.04.1
linux-hwe< 4.15.0-151.157~16.04.1 | All versions (No fix recorded)
linux-hwe-5.4< 5.4.0-77.86~18.04.1
linux-hwe-5.8< 5.8.0-63.71~20.04.1
linux-hwe-edgeAll versions (No fix recorded)
linux-intel-iot-realtimeAll versions (No fix recorded)
linux-kvm< 4.4.0-1100.109 | < 4.15.0-1097.99 | < 5.4.0-1041.42
linux-lts-xenial< 4.4.0-219.252~14.04.1
linux-oemAll versions (No fix recorded)
linux-oem-5.10< 5.10.0-1032.33
linux-oem-5.6All versions (No fix recorded)
linux-oracle< 4.15.0-1078.86~16.04.1 | < 4.15.0-1078.86 | < 5.4.0-1048.52
linux-oracle-5.0All versions (No fix recorded)
linux-oracle-5.3All versions (No fix recorded)
linux-oracle-5.4< 5.4.0-1048.52~18.04.1
linux-oracle-5.8< 5.8.0-1037.38~20.04.1
linux-raspi< 5.4.0-1038.41
linux-raspi-5.4< 5.4.0-1038.41~18.04.1
linux-raspi-realtimeAll versions (No fix recorded)
linux-raspi2< 4.15.0-1092.98 | All versions (No fix recorded)
linux-realtimeAll versions (No fix recorded)
linux-riscvAll versions (No fix recorded)
linux-riscv-5.8All versions (No fix recorded)
linux-snapdragon< 4.15.0-1109.118

Show all 54

Redhat30 products

kpatch-patch-4_18_0-147_24_2< 0:1-10.el8_1
kpatch-patch-4_18_0-147_24_2-debuginfo< 0:1-10.el8_1
kpatch-patch-4_18_0-147_24_2-debugsource< 0:1-10.el8_1
kpatch-patch-4_18_0-147_27_1< 0:1-10.el8_1
kpatch-patch-4_18_0-147_27_1-debuginfo< 0:1-10.el8_1

Show all 30

Debian2 products

linux< 5.10.38-1
debian_linuxEOL9.0

Fedoraproject1 product

fedoraEOL34

Linux1 product

linux_kernel< 4.4.269 | ≥ 4.5, < 4.9.269 | ≥ 4.10, < 4.14.233 | ≥ 4.15, < 4.19.191 | ≥ 4.20, < 5.4.119 | ≥ 5.5, < 5.10.37 | ≥ 5.11, < 5.11.21 | ≥ 5.12, < 5.12.4

5 vendors · 88 products