CVE-2022-49942: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: Don't finalize CSA in IBSS mode if state is disconnected When we are not connected to a channel, sending channel "switch" announcement doesn't make any sense. The BSS list is empty in that case. This causes the for loop in cfg80211_get_bss() to be bypassed, so the function returns NULL (check line 1424 of net/wireless/scan.c), causing the WARN_ON() in ieee80211_ibss_csa_beacon() to get triggered (check line 500 of net/mac80211/ibss.c), which was consequently reported on the syzkaller dashboard. Thus, check if we have an existing connection before generating the CSA beacon in ieee80211_ibss_finish_csa().

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CVSS v3.1 Score

5.5

MEDIUM

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

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	3.13 — 4.9.328
linux	linux_kernel	4.10 — 4.14.293
linux	linux_kernel	4.15 — 4.19.258
linux	linux_kernel	4.20 — 5.4.213
linux	linux_kernel	5.5 — 5.10.142
linux	linux_kernel	5.11 — 5.15.66
linux	linux_kernel	5.16 — 5.19.8
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/15bc8966b6d3a5b9bfe4c9facfa02f2b69b1e5f0 https://git.kernel.org/stable/c/1691a48aef0a82d1754b9853dae7e3f5cacdf70b https://git.kernel.org/stable/c/552ba102a6898630a7d16887f29e606d6fabe508 https://git.kernel.org/stable/c/66689c5c02acd4d76c28498fe220998610aec61e https://git.kernel.org/stable/c/864e280cb3a9a0f5212b16ef5057c4e692f7039d https://git.kernel.org/stable/c/cdb9a8da9b84800eb15506cd9363cf0cf059e677 https://git.kernel.org/stable/c/d9eb37db6a28b59a95a3461450ee209654c5f95b https://git.kernel.org/stable/c/dd649b49219a0388cc10fc40e4c2ea681566a780

Frequently Asked Questions

What is CVE-2022-49942? +

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: Don't finalize CSA in IBSS mode if state is disconnected When we are not connected to a channel, sending channel "switch" announcement doesn't make any sense. The BSS list is empty in that case. This causes the for loop in cfg80211_get_bss() to be bypassed, so the function returns NULL (check line 1424 of net/wireless/scan.c), causing the WARN_ON() in ieee80211_ibss_csa_beacon() to get triggered (check line 500 of net/mac80211/ibss.c), which was consequently reported on the syzkaller dashboard. Thus, check if we have an existing connection before generating the CSA beacon in ieee80211_ibss_finish_csa(). It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2022-49942? +

CVE-2022-49942 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2022-49942? +

CVE-2022-49942 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-2022-49942? +

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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CVE-2022-49942