CVE-2021-33034
HIGHCVSS 7.8/10EPSS 0.82%
Last modified
CVE-2021-33034 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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.. EPSS estimates a 0.82% chance of exploitation in the next 30 days.
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.
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | < 4.4.269 |
| Linux | Linux Kernel | >= 4.5, < 4.9.269 |
| Linux | Linux Kernel | >= 4.10, < 4.14.233 |
| Linux | Linux Kernel | >= 4.15, < 4.19.191 |
| Linux | Linux Kernel | >= 4.20, < 5.4.119 |
| Linux | Linux Kernel | >= 5.5, < 5.10.37 |
| Linux | Linux Kernel | >= 5.11, < 5.11.21 |
| Linux | Linux Kernel | >= 5.12, < 5.12.4 |
| Fedoraproject | Fedora | 34 |
| Debian | Debian Linux | 9.0 |
References
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.4Mailing List, Patch, Vendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5c4c8c9544099bb9043a10a5318130a943e32fc3Mailing List, Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2021/06/msg00019.htmlThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/06/msg00020.htmlThird Party Advisory
- https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-hci_send_aclExploit, Third Party Advisory
- https://syzkaller.appspot.com/bug?id=2e1943a94647f7732dd6fc60368642d6e8dc91b1Exploit, Mailing List, Third Party Advisory
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.4Mailing List, Patch, Vendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5c4c8c9544099bb9043a10a5318130a943e32fc3Mailing List, Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2021/06/msg00019.htmlThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/06/msg00020.htmlThird Party Advisory
- https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-hci_send_aclExploit, Third Party Advisory
- https://syzkaller.appspot.com/bug?id=2e1943a94647f7732dd6fc60368642d6e8dc91b1Exploit, Mailing List, Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2021-33034?
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.
How severe is CVE-2021-33034?
CVE-2021-33034 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.82% probability of exploitation in the next 30 days.
How do I fix CVE-2021-33034?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2021-33034?
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Scan your code nowSource: NVD / NIST