SECUFOCUSNOW
Home›CVE index›CVE-2021-33034
ReviewHigh

CVE-2021-33034

linux kernel, fedora

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
7.8
EPSS
0.82%
54.7% percentile
CISA KEV
Not listed
Published
2021.05.15
PRIORITY ASSESSMENT

Review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.82%
Technical severityCVSS 7.8

Vulnerability overview

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.

Affected product and versions

Product
linux kernel, fedora
Affected versions
< 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, 34, 9.0
Fixed versions
4.4.269, 4.9.269, 4.14.233, 4.19.191, 5.4.119, 5.10.37, 5.11.21, 5.12.4

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that linux kernel, fedora and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-416