How severe is CVE-2021-39638?

CVE-2021-39638 has a CVSS 3.x base score of 6.7, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-39638 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39638?

CVE-2021-39638 affects Google Android. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-39638?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-39638 published?

CVE-2021-39638 was published on 2021-12-15 and last updated on 2026-06-17.

CVE-2021-39638

CVE-2021-39638 is a medium-severity vulnerability in Google Android with a CVSS 3.x base score of 6.7. 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-416.

Key facts

Severity: Medium (CVSS 3.x base score 6.7)
CVSS v2: 4.6
EPSS exploit prediction: 0% (2nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-416
Affected product: Google Android
Published: 2021-12-15
Last modified: 2026-06-17

Description

In periodic_io_work_func of lwis_periodic_io.c, there is a possible out of bounds write due to a use after free. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-195607566References: N/A

Frequently asked questions

What is CVE-2021-39638?: In periodic_io_work_func of lwis_periodic_io.c, there is a possible out of bounds write due to a use after free. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-195607566References: N/A
How severe is CVE-2021-39638?: CVE-2021-39638 has a CVSS 3.x base score of 6.7, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-39638 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39638?: CVE-2021-39638 affects Google Android. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-39638?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-39638 published?: CVE-2021-39638 was published on 2021-12-15 and last updated on 2026-06-17.

References

https://source.android.com/security/bulletin/pixel/2021-12-01

Affected products (1)

cpe:2.3:o:google:android:-:*:*:*:*:*:*:*

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