Use After Free in Linux Kernel
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.
Vulnerability class: Use-After-Free
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.008 (55.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 55.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000
Affected products
- Linux Kernel
- Debian Linux — versions 9.0
- Fedoraproject Fedora — versions 34
Weakness classification (CWE)
Public proof-of-concept exploits
References
- syzkaller.appspot.com/bug (Exploit, Mailing List, Third Party Advisory)
- sites.google.com/view/syzscope/kasan-use-after-free-read-in-hci_send_acl (Exploit, Third Party Advisory)
- git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ (Patch, Mailing List, Vendor Advisory)
- cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.4 (Patch, Mailing List, Vendor Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory, Broken Link)
- lists.debian.org/debian-lts-announce/2021/06/msg00020.html (mailing-list, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2021/06/msg00019.html (mailing-list, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-33034?
- CVE-2021-33034 is a high-severity vulnerability in Linux Kernel, classified under Use After Free. CVSS score: 7.8/10. Published 2021-05-14.
- How severe is CVE-2021-33034?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2021-33034 known to be exploited?
- 11 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.