CVE-2021-33034
Status: AnalyzedHigh (7.8)—💥 PoC
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
- Version: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Base score: 7.8
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days: 0.83%
- Percentile among all scored CVEs: 56
- Score date: 10/12/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
💥 Public exploits
Exploit code or detection templates are publicly available. This is not the same as confirmed active exploitation (KEV), but it raises the risk: patch with priority.
- Proof of concept on GitHub (unverified) · List of proofs of concept on GitHub
⚠️ GitHub proofs of concept are not verified: some are fake or contain malware. Never run them outside an isolated lab.
Affected technologies (3)
CWEs
- CWE-416
References
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.4
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5c4c8c9544099bb9043a10a5318130a943e32fc3
- https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html
- https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GI7Z7UBWBGD3ABNIL2DC7RQDCGA4UVQW/
- https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-hci_send_acl
- https://syzkaller.appspot.com/bug?id=2e1943a94647f7732dd6fc60368642d6e8dc91b1
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.4
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5c4c8c9544099bb9043a10a5318130a943e32fc3
- https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html
- https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GI7Z7UBWBGD3ABNIL2DC7RQDCGA4UVQW/
- https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-hci_send_acl
- https://syzkaller.appspot.com/bug?id=2e1943a94647f7732dd6fc60368642d6e8dc91b1
Raw JSON (NVD)
Show
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