CVE-2021-21848
Telemetry drift only. No threshold crossed and no authority ruling changed.
CVE record loaded 2026-09-20.
What to do now held facts and links
- No fix version is held. The CNA's first reference is the place to look: talosintelligence.com
- Record your decision, dated and frozen with today's evidence: patch by a date · mitigated by a compensating control · deferred · accepted the risk · not affected
- Check your version against the ranges this record publishes.
What it is stated by the CNA
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.
- weakness
- CWE-680: Integer Overflow to Buffer Overflow
- affected
- n/a GPAC Project
- versions
- n/a GPAC Project GPAC Project Advanced Content commit a8a8d412dabcb129e695c3e7d861fcc81f608304,GPAC Project Advanced Content v1.0.1
- published ranges
- gpac 1.0.1; debian linux 10.0; debian linux 11.0
- fixed in
- No fix version in held sources.
- severity
- 8.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- assigned by
- talos
- published
- 2021-08-25
check us talosintelligence.com debian.org
Exploit code held, dated
- exploit code
- None held in the PoC-in-GitHub feed. A public repository changes this brief.
What moved held, dated
| date | EPSS | event |
|---|---|---|
| 26 Aug 2021 | 0.0034 | |
| 1 Sep 2021 | 0.0051 | |
| 6 Jan 2022 | 0.02249 | |
| 4 Feb 2022 | 0.05246 | |
| 7 Mar 2023 | 0.00121 | scoring model v2023.03.01 |
| 17 Mar 2025 | 0.00475 | scoring model v2025.03.14 |
| 18 Nov 2025 | 0.00561 | |
| 21 Nov 2025 | 0.00245 | |
| 15 Jun 2026 | 0.01577 | scoring model v2026.06.15 |
| 18 Jun 2026 | 0.01695 |
20 observations held. A step marked with a scoring model moved because the measurement was replaced, not because the vulnerability changed.
Outside the record researched, cited
This section reads the record's references and adds cited findings from outside it. It needs an account. Everything above is held facts and is complete without it.
What would change this brief held, dated
- CISA KEV
- Not listed in the catalogue we hold. A listing changes this brief.
- exploit probability
- 0.02 on 2026-06-18 (FIRST's EPSS, a probability and not evidence of exploitation). Next band line: 10% (0.10). Crossing a line changes this brief.
- fix
- No fix version is held. One published by the CNA or OSV changes this brief.
How to check this
Every value above is held with two dates: when it was true upstream (as_of) and when we recorded it (tx_from). Re-derive the exploit probability as it stood on any date:
SELECT value, source, source_version, as_of, tx_from
FROM volatile_valid_as_of('CVE-2021-21848', '2026-10-03T23:59:59.999999Z', now());Identity above is quoted from the CVE Program record, corpus cvelistv5_20260920, recorded 30 Sep 2026.