CVE-2021-47295: linux kernel DoS — Fix

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.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-400 Uncontrolled Resource Consumption

Affected Products

Vendor	Product	Versions
linux	linux_kernel	3.18 — 5.4.136
linux	linux_kernel	5.5 — 5.10.54
linux	linux_kernel	5.11 — 5.13.6
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/8d7924ce85bae64e7a67c366c7c50840f49f3a62 https://git.kernel.org/stable/c/8e9662fde6d63c78eb1350f6167f64c9d71a865b https://git.kernel.org/stable/c/cac71d27745f92ee13f0ecc668ffe151a4a9c9b1 https://git.kernel.org/stable/c/f5051bcece50140abd1a11a2d36dc3ec5484fc32 https://git.kernel.org/stable/c/8d7924ce85bae64e7a67c366c7c50840f49f3a62 https://git.kernel.org/stable/c/8e9662fde6d63c78eb1350f6167f64c9d71a865b https://git.kernel.org/stable/c/cac71d27745f92ee13f0ecc668ffe151a4a9c9b1 https://git.kernel.org/stable/c/f5051bcece50140abd1a11a2d36dc3ec5484fc32

Other References

https://git.kernel.org/stable/c/01d0d2b8b4e3cf2110baba9371c0c3d04ad5c77b https://git.kernel.org/stable/c/18c3fa7a7fdbb4d21dafc8a7710ae2c1680930f6 https://git.kernel.org/stable/c/372ae77cf11d11fb118cbe2d37def9dd5f826abd https://git.kernel.org/stable/c/3abebc503a5148072052c229c6b04b329a420ecd https://git.kernel.org/stable/c/53af9c793f644d5841d84d8e0ad83bd7ab47f3e0 https://git.kernel.org/stable/c/7a6fb69bbcb21e9ce13bdf18c008c268874f0480 https://git.kernel.org/stable/c/7c183dc0af472dec33d2c0786a5e356baa8cad19

Frequently Asked Questions

What is CVE-2021-47295? +

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2021-47295? +

CVE-2021-47295 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2021-47295? +

CVE-2021-47295 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-47295? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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