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CVE-2022-49889

ring-buffer: Check for NULL cpu_buffer in ring_buffer_wake_waiters()

Medium5.5EPSS 0.20%
Published
Updated
Reserved
Assigned by
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Check for NULL cpu_buffer in ring_buffer_wake_waiters() On some machines the number of listed CPUs may be bigger than the actual CPUs that exist. The tracing subsystem allocates a per_cpu directory with access to the per CPU ring buffer via a cpuX file. But to save space, the ring buffer will only allocate buffers for online CPUs, even though the CPU array will be as big as the nr_cpu_ids. With the addition of waking waiters on the ring buffer when closing the file, the ring_buffer_wake_waiters() now needs to make sure that the buffer is allocated (with the irq_work allocated with it) before trying to wake waiters, as it will cause a NULL pointer dereference. While debugging this, I added a NULL check for the buffer itself (which is OK to do), and also NULL pointer checks against buffer->buffers (which is not fine, and will WARN) as well as making sure the CPU number passed in is within the nr_cpu_ids (which is also not fine if it isn't). Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=1204705

Scores

CVSS scores of CVE-2022-49889, by who scored it
Scored byCVSSScoreVector
CISA-ADPADP (enrichment)3.1Medium5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVDNVD · Modified3.1Medium5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS (exploitation in 30 days)
0.20% · top 90% of all CVEs (6 Nov 2026)
CISA SSVC
Exploitation: none · Automatable: no · Technical impact: partial
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.

Weakness

Affected products

  • Linux · Linux

    • affected 2475de2bc0de17fb1b24c5e90194f84b5ca70d3e – < b5074df412bf3df9d6ce096b6fa03eb1082d05c9
    • affected f4f15344110d0b5b8822ac97bc8200e71939c945 – < 49ca992f6e50d0f46ec9608f44e011cf3121f389
    • affected f3ddb74ad0790030c9592229fb14d8c451f4e9a8 – < 7433632c9ff68a991bd0bc38cabf354e9d2de410
    • affected 5544f411a4e8bc39e6a444badbac37dd0e0caf0a
    • affected 5.19.17 – < 5.20

  • Linux · Linux

    • affected 5.15.75 – < 5.15.78
    • affected 6.0.3 – < 6.0.8

References (3)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .