How severe is CVE-2021-39623?

CVE-2021-39623 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-39623 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39623?

CVE-2021-39623 primarily affects Google Android. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-39623?

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

When was CVE-2021-39623 published?

CVE-2021-39623 was published on 2022-01-14 and last updated on 2026-06-17.

CVE-2021-39623

CVE-2021-39623 is a critical-severity vulnerability in Google Android with a CVSS 3.x base score of 9.8. 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-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 2% (79th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Google Android
Published: 2022-01-14
Last modified: 2026-06-17

Description

In doRead of SimpleDecodingSource.cpp, there is a possible out of bounds write due to an incorrect bounds check. This could lead to remote escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-10 Android-11 Android-12 Android-9Android ID: A-194105348

Frequently asked questions

What is CVE-2021-39623?: In doRead of SimpleDecodingSource.cpp, there is a possible out of bounds write due to an incorrect bounds check. This could lead to remote escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-10 Android-11 Android-12 Android-9Android ID: A-194105348
How severe is CVE-2021-39623?: CVE-2021-39623 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-39623 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39623?: CVE-2021-39623 primarily affects Google Android. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-39623?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-39623 published?: CVE-2021-39623 was published on 2022-01-14 and last updated on 2026-06-17.

References

https://source.android.com/security/bulletin/2022-01-01

Affected products (4)

cpe:2.3:o:google:android:9.0:*:*:*:*:*:*:*
cpe:2.3:o:google:android:10.0:*:*:*:*:*:*:*
cpe:2.3:o:google:android:11.0:*:*:*:*:*:*:*
cpe:2.3:o:google:android:12.0:*:*:*:*:*:*:*

More vulnerabilities in Google Android

CVE-2026-0092 — Critical (CVSS 10.0): In Package Manager, there is a possible device lock controller bypass due to a missing permission check. This could…
CVE-2025-48611 — Critical (CVSS 10.0): In DeviceId of DeviceId.java, there is a possible desync in persistence due to a missing bounds check. This could lead…
CVE-2015-8073 — Critical (CVSS 10.0): mediaserver in Android 4.4 and 5.1 before 5.1.1 LMY48X allows remote attackers to execute arbitrary code or cause a…
CVE-2015-8072 — Critical (CVSS 10.0): mediaserver in Android 4.4 through 5.x before 5.1.1 LMY48X and 6.0 before 2015-11-01 allows remote attackers to execute…
CVE-2015-6610 — Critical (CVSS 10.0): libstagefright in Android before 5.1.1 LMY48X and 6.0 before 2015-11-01 allows attackers to gain privileges or cause a…
CVE-2015-6609 — Critical (CVSS 10.0): libutils in Android before 5.1.1 LMY48X and 6.0 before 2015-11-01 allows remote attackers to execute arbitrary code or…

All CVEs affecting Google Android →

Other CWE-787 (Out-of-bounds Write) vulnerabilities

CVE-2026-42369 — Critical (CVSS 10.0): GV-VMS V20 is a Video Monitoring Software used to gather the feeds of many surveillance cameras and manage other…
CVE-2026-4746 — Critical (CVSS 10.0): Out-of-bounds Write vulnerability in timeplus-io proton (base/poco/Foundation/src‎ modules). This vulnerability is…
CVE-2025-43300 — Critical (CVSS 10.0): An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 15.8.5 and iPadOS…
CVE-2025-24201 — Critical (CVSS 10.0): An out-of-bounds write issue was addressed with improved checks to prevent unauthorized actions. This issue is fixed in…
CVE-2024-42479 — Critical (CVSS 10.0): llama.cpp provides LLM inference in C/C++. The unsafe `data` pointer member in the `rpc_tensor` structure can cause…
CVE-2024-39791 — Critical (CVSS 10.0): Stack-based buffer overflow vulnerabilities affecting Vonets industrial wifi bridge relays and wifi bridge…

Browse all CWE-787 (Out-of-bounds Write) vulnerabilities →