Out-of-bounds Read in Linux Kernel
CVE-2021-3444
The bpf verifier in the Linux kernel did not properly handle mod32 destination register truncation when the source register was known to be 0. A local attacker with the ability to load bpf programs could use this gain out-of-bounds reads in kernel memory leading to information disclosure (kernel memory), and possibly out-of-bounds writes that could potentially lead to code execution. This issue was addressed in the upstream kernel in commit 9b00f1b78809 ("bpf: Fix truncation handling for mod32 dst reg wrt zero") and in Linux stable kernels 5.11.2, 5.10.19, and 5.4.101.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.006 (47.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Linux Kernel — versions trunk, 5.11, 5.10
- Linux Kernel
- Canonical Ubuntu Linux — versions 14.04, 16.04, 18.04
- Debian Linux — versions 9.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ (Patch, Mailing List, Vendor Advisory)
- www.openwall.com/lists/oss-security/2021/03/23/2 (Mailing List, Third Party Advisory)
- www.openwall.com/lists/oss-security/2021/03/23/2 (mailing-list, Mailing List, Third Party Advisory)
- packetstormsecurity.com/files/162117/Kernel-Live-Patch-Security-Notice-LSN-0075… (VDB Entry, Third Party Advisory)
- security.netapp.com/advisory/ntap-20210416-0006/ (Third Party Advisory)
- lists.debian.org/debian-lts-announce/2021/10/msg00010.html (mailing-list, Mailing List, Third Party Advisory)
- packetstormsecurity.com/files/164950/Kernel-Live-Patch-Security-Notice-LSN-0082… (VDB Entry, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-3444?
- CVE-2021-3444 is a high-severity vulnerability in Linux Kernel, classified under Incorrect Conversion between Numeric Types. CVSS score: 7.8/10. Published 2021-03-23.
- How severe is CVE-2021-3444?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2021-3444 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.