CVE-2021-4202: Use After Free
First published: Mon Jan 03 2022(Updated: )
A flaw was found in the Linux kernel. Similar to the <a href="https://access.redhat.com/security/cve/CVE-2021-35373">CVE-2021-35373</a>, the nci_request() function in NFC NCI code also suffers from a data race. This race will allow __nci_request() to be awaken while the device is getting removed and cause UAF. The attacker can spray the released object to gain powerful primitive. Upstream commit: <a href="https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=86cdf8e38792545161dbe3350a7eced558ba4d15">https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=86cdf8e38792545161dbe3350a7eced558ba4d15</a> <a href="https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=48b71a9e66c2eab60564b1b1c85f4928ed04e406">https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=48b71a9e66c2eab60564b1b1c85f4928ed04e406</a> <a href="https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3e3b5dfcd16a3e254aab61bd1e8c417dd4503102">https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3e3b5dfcd16a3e254aab61bd1e8c417dd4503102</a> <a href="https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=aedddb4e45b34426cfbfa84454b6f203712733c5">https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=aedddb4e45b34426cfbfa84454b6f203712733c5</a>
Credit: secalert@redhat.com secalert@redhat.com secalert@redhat.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| redhat/kernel | <5.16 | 5.16 |
| Linux Kernel | >=3.2<4.4.294 | |
| Linux Kernel | >=4.5<4.9.292 | |
| Linux Kernel | >=4.10<4.14.257 | |
| Linux Kernel | >=4.15<4.19.219 | |
| Linux Kernel | >=4.20<5.4.163 | |
| Linux Kernel | >=5.5.0<5.10.82 | |
| Linux Kernel | >=5.11<5.15.5 | |
| debian/linux | 5.10.223-1 5.10.226-1 6.1.123-1 6.1.119-1 6.12.11-1 6.12.12-1 |
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Reference Links
- http://www.openwall.com/lists/oss-security/2022/06/01/2
- http://www.openwall.com/lists/oss-security/2022/06/04/2
- http://www.openwall.com/lists/oss-security/2022/06/07/2
- https://bugzilla.redhat.com/show_bug.cgi?id=2036682
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3e3b5dfcd16a3e254aab61bd1e8c417dd4503102
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=48b71a9e66c2eab60564b1b1c85f4928ed04e406
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=86cdf8e38792545161dbe3350a7eced558ba4d15
- https://security.netapp.com/advisory/ntap-20220513-0002/
- https://launchpad.net/bugs/cve/CVE-2021-4202
- https://access.redhat.com/security/cve/CVE-2021-35373
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=aedddb4e45b34426cfbfa84454b6f203712733c5
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-4202
- https://nvd.nist.gov/vuln/detail/CVE-2021-4202
- https://security-tracker.debian.org/tracker/CVE-2021-4202
- https://ubuntu.com/security/CVE-2021-4202
Frequently Asked Questions
What is the severity of CVE-2021-4202?
CVE-2021-4202 is classified as a medium-severity vulnerability due to the potential for data races within the Linux kernel.
How do I fix CVE-2021-4202?
To mitigate CVE-2021-4202, upgrade to the Linux kernel version 5.16 or higher.
Which systems are affected by CVE-2021-4202?
CVE-2021-4202 affects multiple versions of the Linux kernel, specifically those between versions 3.2 and 5.15.
What component in the kernel is affected by CVE-2021-4202?
The vulnerability in CVE-2021-4202 is found in the nci_request() function within the NFC NCI code of the Linux kernel.
Is CVE-2021-4202 similar to any other vulnerabilities?
Yes, CVE-2021-4202 is similar to CVE-2021-35373 as both involve data races in the Linux kernel.
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