CVE-2021-33034

Public Exploit

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.

Category

7.8
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.11%
Vendor Advisory fedoraproject.org Vendor Advisory kernel.org Vendor Advisory kernel.org
Affected: n/a n/a
Published at:
Updated at:

References

Link Tags
https://syzkaller.appspot.com/bug?id=2e1943a94647f7732dd6fc60368642d6e8dc91b1 mailing list exploit third party advisory
https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-hci_send_acl third party advisory exploit
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5c4c8c9544099bb9043a10a5318130a943e32fc3 mailing list patch vendor advisory
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.4 mailing list patch vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GI7Z7UBWBGD3ABNIL2DC7RQDCGA4UVQW/ vendor advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html third party advisory mailing list
https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html third party advisory mailing list

Frequently Asked Questions

What is the severity of CVE-2021-33034?
CVE-2021-33034 has been scored as a high severity vulnerability.
How to fix CVE-2021-33034?
To fix CVE-2021-33034, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-33034 being actively exploited in the wild?
It is possible that CVE-2021-33034 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.