CVE-2021-3444
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.61%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.61% probability · 47th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-681, CWE-125
- Affected
- linux/linux kernel · debian/debian linux · canonical/ubuntu linux
- Source
- security@ubuntu.com
References
- http://packetstormsecurity.com/files/162117/Kernel-Live-Patch-Security-Notice-LSN-0075-1.htmlThird Party Advisory, VDB Entry
- http://packetstormsecurity.com/files/164950/Kernel-Live-Patch-Security-Notice-LSN-0082-1.htmlThird Party Advisory, VDB Entry
- http://www.openwall.com/lists/oss-security/2021/03/23/2Mailing List, Third Party Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9b00f1b78809Mailing List, Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2021/10/msg00010.htmlMailing List, Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210416-0006/Third Party Advisory
- https://www.openwall.com/lists/oss-security/2021/03/23/2Mailing List, Third Party Advisory
- http://packetstormsecurity.com/files/162117/Kernel-Live-Patch-Security-Notice-LSN-0075-1.htmlThird Party Advisory, VDB Entry
- http://packetstormsecurity.com/files/164950/Kernel-Live-Patch-Security-Notice-LSN-0082-1.htmlThird Party Advisory, VDB Entry
- http://www.openwall.com/lists/oss-security/2021/03/23/2Mailing List, Third Party Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9b00f1b78809Mailing List, Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2021/10/msg00010.htmlMailing List, Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210416-0006/Third Party Advisory
- https://www.openwall.com/lists/oss-security/2021/03/23/2Mailing List, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.