CVE-2022-49648

CVE-2022-49648 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-401.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: tracing/histograms: Fix memory leak problem This reverts commit 46bbe5c671e06f070428b9be142cc4ee5cedebac. As commit 46bbe5c671e0 ("tracing: fix double free") said, the "double free" problem reported by clang static analyzer is: > In parse_var_defs() if there is a problem allocating > var_defs.expr, the earlier var_defs.name is freed. > This free is duplicated by free_var_defs() which frees > the rest of the list. However, if there is a problem allocating N-th var_defs.expr: + in parse_var_defs(), the freed 'earlier var_defs.name' is actually the N-th var_defs.name; + then in free_var_defs(), the names from 0th to (N-1)-th are freed; IF ALLOCATING PROBLEM HAPPENED HERE!!! -+ \ | 0th 1th (N-1)-th N-th V +-------------+-------------+-----+-------------+----------- var_defs: | name | expr | name | expr | ... | name | expr | name | /// +-------------+-------------+-----+-------------+----------- These two frees don't act on same name, so there was no "double free" problem before. Conversely, after that commit, we get a "memory leak" problem because the above "N-th var_defs.name" is not freed. If enable CONFIG_DEBUG_KMEMLEAK and inject a fault at where the N-th var_defs.expr allocated, then execute on shell like: $ echo 'hist:key=call_site:val=$v1,$v2:v1=bytes_req,v2=bytes_alloc' > \ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger Then kmemleak reports: unreferenced object 0xffff8fb100ef3518 (size 8): comm "bash", pid 196, jiffies 4295681690 (age 28.538s) hex dump (first 8 bytes): 76 31 00 00 b1 8f ff ff v1...... backtrace: [<0000000038fe4895>] kstrdup+0x2d/0x60 [<00000000c99c049a>] event_hist_trigger_parse+0x206f/0x20e0 [<00000000ae70d2cc>] trigger_process_regex+0xc0/0x110 [<0000000066737a4c>] event_trigger_write+0x75/0xd0 [<000000007341e40c>] vfs_write+0xbb/0x2a0 [<0000000087fde4c2>] ksys_write+0x59/0xd0 [<00000000581e9cdf>] do_syscall_64+0x3a/0x80 [<00000000cf3b065c>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

Frequently asked questions

What is CVE-2022-49648?
In the Linux kernel, the following vulnerability has been resolved: tracing/histograms: Fix memory leak problem This reverts commit 46bbe5c671e06f070428b9be142cc4ee5cedebac. As commit 46bbe5c671e0 ("tracing: fix double free") said, the "double free" problem reported by clang static analyzer is: > In parse_var_defs() if there is a problem allocating > var_defs.expr, the earlier var_defs.name is freed. > This free is duplicated by free_var_defs() which frees > the rest of the list. However, if there is a problem allocating N-th var_defs.expr: + in parse_var_defs(), the freed 'earlier var_defs.name' is actually the N-th var_defs.name; + then in free_var_defs(), the names from 0th to (N-1)-th are freed; IF ALLOCATING PROBLEM HAPPENED HERE!!! -+ \ | 0th 1th (N-1)-th N-th V +-------------+-------------+-----+-------------+----------- var_defs: | name | expr | name | expr | ... | name | expr | name | /// +-------------+-------------+-----+-------------+----------- These two frees don't act on same name, so there was no "double free" problem before. Conversely, after that commit, we get a "memory leak" problem because the above "N-th var_defs.name" is not freed. If enable CONFIG_DEBUG_KMEMLEAK and inject a fault at where the N-th var_defs.expr allocated, then execute on shell like: $ echo 'hist:key=call_site:val=$v1,$v2:v1=bytes_req,v2=bytes_alloc' > \ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger Then kmemleak reports: unreferenced object 0xffff8fb100ef3518 (size 8): comm "bash", pid 196, jiffies 4295681690 (age 28.538s) hex dump (first 8 bytes): 76 31 00 00 b1 8f ff ff v1...... backtrace: [<0000000038fe4895>] kstrdup+0x2d/0x60 [<00000000c99c049a>] event_hist_trigger_parse+0x206f/0x20e0 [<00000000ae70d2cc>] trigger_process_regex+0xc0/0x110 [<0000000066737a4c>] event_trigger_write+0x75/0xd0 [<000000007341e40c>] vfs_write+0xbb/0x2a0 [<0000000087fde4c2>] ksys_write+0x59/0xd0 [<00000000581e9cdf>] do_syscall_64+0x3a/0x80 [<00000000cf3b065c>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
How severe is CVE-2022-49648?
CVE-2022-49648 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2022-49648 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-49648?
CVE-2022-49648 primarily affects Linux Linux Kernel. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2022-49648?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2022-49648 have an EU (EUVD) identifier?
Yes. CVE-2022-49648 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2022-54584.
When was CVE-2022-49648 published?
CVE-2022-49648 was published on 2025-02-26 and last updated on 2026-06-17.

References

Affected products (7)

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