CVE-2021-21848
CVSS v3
8.8
HIGH
EPSS Score
1.7 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
An exploitable integer overflow vulnerability exists within the MPEG-4 decoding functionality of the GPAC Project on Advanced Content library v1.0.1. The library will actually reuse the parser for atoms with the “stsz” FOURCC code when parsing atoms that use the “stz2” FOURCC code and can cause an integer overflow due to unchecked arithmetic resulting in a heap-based buffer overflow that causes memory corruption. An attacker can convince a user to open a video to trigger this vulnerability.
Technical details
- Published
- 2021-08-25
Frequently asked questions
What is CVE-2021-21848?
An exploitable integer overflow vulnerability exists within the MPEG-4 decoding functionality of the GPAC Project on Advanced Content library v1.0.1. The library will actually reuse the parser for atoms with the “stsz” FOURCC code when parsing atoms that use the “stz2” FOURCC code and can cause an integer overflow due to unchecked arithmetic resulting in a heap-based buffer overflow that causes memory corruption. An attacker can convince a user to open a video to trigger this vulnerability.
Is CVE-2021-21848 actively exploited?
Active exploitation of CVE-2021-21848 has not been confirmed. Its EPSS score was 1.7% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-21848?
CVE-2021-21848 has a CVSS v3 base score of 8.8 (HIGH severity).
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