CVE-2021-47295: net: sched: fix memory leak in tcindex_partial_destroy_work

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-21 · updated 2026-06-17
Weakness: CWE-400

Description

In the Linux kernel, the following vulnerability has been resolved: net: sched: fix memory leak in tcindex_partial_destroy_work Syzbot reported memory leak in tcindex_set_parms(). The problem was in non-freed perfect hash in tcindex_partial_destroy_work(). In tcindex_set_parms() new tcindex_data is allocated and some fields from old one are copied to new one, but not the perfect hash. Since tcindex_partial_destroy_work() is the destroy function for old tcindex_data, we need to free perfect hash to avoid memory leak.

Affected products

Linux kernel: from 3.18 before 5.4.136; from 5.5 before 5.10.54; from 5.11 before 5.13.6; 5.14-rc1, 5.14-rc2 — fixed in 5.10.54, 5.13.6, 5.4.136

How to fix

Upgrade to a fixed version: Linux kernel 5.10.54, 5.13.6, 5.4.136. Check the vendor advisory for mitigations.

References

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