CVE-2021-33200
First published: Wed May 26 2021(Updated: )
A flaw was found in kernel/bpf/verifier.c in BPF in the Linux kernel. An incorrect limit is enforced for pointer arithmetic operations which can be abused to perform out-of-bounds reads and writes in kernel memory, leading to local privilege escalation. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Credit: cve@mitre.org cve@mitre.org cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| redhat/kernel-rt | <0:4.18.0-348.rt7.130.el8 | 0:4.18.0-348.rt7.130.el8 |
| redhat/kernel | <0:4.18.0-348.el8 | 0:4.18.0-348.el8 |
| redhat/kernel | <5.13 | 5.13 |
| debian/linux | 5.10.223-1 5.10.226-1 6.1.123-1 6.1.128-1 6.12.12-1 6.12.15-1 | |
| Linux Kernel | >=5.4.116<5.4.123 | |
| Linux Kernel | >=5.10.33<5.10.41 | |
| Linux Kernel | >=5.11.17<5.12.8 | |
| Fedora | =33 | |
| Fedora | =34 | |
| netapp cloud backup | ||
| netapp solidfire \& hci management node | ||
| netapp solidfire baseboard management controller | ||
| All of | ||
| netapp h300s | ||
| netapp h300s firmware | ||
| All of | ||
| netapp h500s | ||
| NetApp H500S Firmware | ||
| All of | ||
| netapp h300e | ||
| netapp h300e firmware | ||
| All of | ||
| netapp h500e | ||
| netapp h500e firmware | ||
| All of | ||
| netapp h700e | ||
| netapp h700e firmware | ||
| All of | ||
| netapp h410s | ||
| netapp h410s firmware | ||
| All of | ||
| netapp h700s | ||
| netapp h700s firmware | ||
| netapp h300s firmware | ||
| netapp h300s | ||
| NetApp H500S Firmware | ||
| netapp h500s | ||
| netapp h300e firmware | ||
| netapp h300e | ||
| netapp h500e firmware | ||
| netapp h500e | ||
| netapp h700e firmware | ||
| netapp h700e | ||
| netapp h410s firmware | ||
| netapp h410s | ||
| netapp h700s firmware | ||
| netapp h700s |
Remedy
The default Red Hat Enterprise Linux kernel prevents unprivileged users from being able to use eBPF by the kernel.unprivileged_bpf_disabled sysctl. This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space. For the Red Hat Enterprise Linux 7 the eBPF for unprivileged users is always disabled. For the Red Hat Enterprise Linux 8 to confirm the current state, inspect the sysctl with the command: # cat /proc/sys/kernel/unprivileged_bpf_disabled The setting of 1 would mean that unprivileged users can not use eBPF, mitigating the flaw. A kernel update will be required to mitigate the flaw for the root or users with CAP_SYS_ADMIN capabilities.
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Reference Links
- https://www.cve.org/CVERecord?id=CVE-2021-33200 https://nvd.nist.gov/vuln/detail/CVE-2021-33200 https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/patch/?id=3d0220f6861d713213b015b582e9f21e5b28d2e0 https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/patch/?id=a7036191277f9fa68d92f2071ddc38c09b1e5ee5 https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/patch/?id=bb01a1bba579b4b1c5566af24d95f1767859771e https://www.openwall.com/lists/oss-security/2021/05/27/1
- https://bugzilla.redhat.com/show_bug.cgi?id=1965458
- https://access.redhat.com/errata/RHSA-2021:4140
- https://access.redhat.com/errata/RHSA-2021:4356
- https://access.redhat.com/security/cve/cve-2021-33200
- https://www.openwall.com/lists/oss-security/2021/05/27/1
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1965460
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JJCABL43FT3FKRX5DBPZG25FNKR6CEK4/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7LR3OKKPHIBGOMHN476CMLW2T7UG53QX/
- https://security.netapp.com/advisory/ntap-20210706-0004/
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=3d0220f6861d713213b015b582e9f21e5b28d2e0
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=a7036191277f9fa68d92f2071ddc38c09b1e5ee5
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bb01a1bba579b4b1c5566af24d95f1767859771e
- https://launchpad.net/bugs/cve/CVE-2021-33200
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7LR3OKKPHIBGOMHN476CMLW2T7UG53QX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JJCABL43FT3FKRX5DBPZG25FNKR6CEK4/
- https://security-tracker.debian.org/tracker/CVE-2021-33200
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-33200
- https://nvd.nist.gov/vuln/detail/CVE-2021-33200
- https://ubuntu.com/security/CVE-2021-33200
Frequently Asked Questions
What is the severity of CVE-2021-33200?
CVE-2021-33200 has a high severity level due to its potential for local privilege escalation through out-of-bounds memory access.
How do I fix CVE-2021-33200?
To fix CVE-2021-33200, update the Linux kernel to a version that addresses this vulnerability, such as kernel-rt 0:4.18.0-348.rt7.130.el8 or kernel 0:4.18.0-348.el8.
What types of systems are affected by CVE-2021-33200?
CVE-2021-33200 affects various versions of the Linux kernel, including specific Red Hat and Debian distributions.
Can CVE-2021-33200 be exploited remotely?
CVE-2021-33200 cannot be exploited remotely; it requires local access to the affected system.
What should I do if I'm running an affected version of the Linux kernel related to CVE-2021-33200?
If running an affected version, immediately plan to update to a secured version of the Linux kernel to mitigate the risk of privilege escalation.
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- version/fedora/33
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- vendor/netapp
- canonical/netapp cloud backup
- canonical/netapp solidfire \& hci management node
- canonical/netapp solidfire baseboard management controller
- canonical/netapp h300s
- canonical/netapp h300s firmware
- canonical/netapp h500s
- canonical/netapp h500s firmware
- canonical/netapp h300e
- canonical/netapp h300e firmware
- canonical/netapp h500e
- canonical/netapp h500e firmware
- canonical/netapp h700e
- canonical/netapp h700e firmware
- canonical/netapp h410s
- canonical/netapp h410s firmware
- canonical/netapp h700s
- canonical/netapp h700s firmware