PT-2024-11116 · Linux+2 · Linux Kernel+2
Shuang Li
·
Published
2021-04-26
·
Updated
2026-03-14
·
CVE-2021-47014
CVSS v3.1
7.8
High
| Vector | AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Name of the Vulnerable Software and Affected Versions
Linux kernel versions prior to 5.12.0-rc7+
Description
The vulnerability is related to a wild memory access issue when clearing fragments while testing re-assembly/re-fragmentation using act ct. This can cause a crash and potentially lead to "wild" memory accesses later when the rbtree is purged. The issue occurs when act ct temporarily stores an IP fragment and restoring the skb qdisc cb results in putting random data in FRAG CB().
Recommendations
To resolve the issue, update the Linux kernel to a version later than 5.12.0-rc7+.
As a temporary workaround, consider disabling the
tcf ct handle fragments() function until a patch is available.
Restrict access to the vulnerable module act ct to minimize the risk of exploitation.
Avoid using the FRAG CB() variable in the affected API endpoint until the issue is resolved.Fix
Improper Check for Exceptional Conditions
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Weakness Enumeration
Related Identifiers
Affected Products
Debian
Linux Kernel
Suse