How severe is CVE-2021-39640?

CVE-2021-39640 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-39640 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39640?

CVE-2021-39640 affects Google Android. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-39640?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-39640 published?

CVE-2021-39640 was published on 2021-12-15 and last updated on 2026-06-17.

CVE-2021-39640

CVE-2021-39640 is a high-severity vulnerability in Google Android with a CVSS 3.x base score of 7.8. 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-667.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 7.2
EPSS exploit prediction: 0% (1st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-667
Affected product: Google Android
Published: 2021-12-15
Last modified: 2026-06-17

Description

In __dwc3_gadget_ep0_queue of ep0.c, there is a possible out of bounds write due to improper locking. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-157294279References: N/A

Frequently asked questions

What is CVE-2021-39640?: In __dwc3_gadget_ep0_queue of ep0.c, there is a possible out of bounds write due to improper locking. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-157294279References: N/A
How severe is CVE-2021-39640?: CVE-2021-39640 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-39640 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39640?: CVE-2021-39640 affects Google Android. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-39640?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-39640 published?: CVE-2021-39640 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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