Security readout for executives and security teams
Plain-English summary
This flaw can let a malicious MPEG-4 video corrupt memory in GPAC when a user or system opens it. Because GPAC is used for multimedia processing, exposure is highest where untrusted media files are opened or processed automatically. The cited data rates it high severity.
Executive priority
Treat as high priority where GPAC processes external media or user-submitted video. For limited internal-only use, prioritize inventory and vendor-guided patching within the high-severity remediation window.
Technical view
CVE-2021-21844 is an integer overflow in GPAC Advanced Content v1.0.1 MPEG-4 decoding. A crafted input involving an stco FOURCC atom can trigger unchecked arithmetic, causing heap-based buffer overflow and memory corruption. The CVSS 3.0 score is 8.8.
Likely exposure
Likely exposure is limited to environments running affected GPAC builds, including GPAC v1.0.1 or the cited commit, especially where GPAC opens or processes externally supplied MPEG-4 files.
Exploitation context
The source states exploitation requires convincing a user to open a specially crafted video. The bundle marks KEV as false and provides no evidence of active exploitation.
Researcher notes
The issue maps to CWE-680: integer overflow leading to buffer overflow. Available evidence identifies the vulnerable parsing path and trigger class, but this response intentionally omits exploit details and payload guidance.
Mitigation direction
- Inventory GPAC, libgpac, and related multimedia processing deployments.
- Apply GPAC or operating-system vendor updates where available.
- Review Debian DSA-4966 if using Debian-packaged GPAC.
- Avoid processing untrusted MPEG-4 files with affected GPAC versions.
- Sandbox or isolate media processing workflows until updated.
Validation and detection
- Confirm installed GPAC versions against the affected v1.0.1 and cited commit.
- Check SBOMs and package manifests for GPAC dependencies.
- Identify workflows that accept user-supplied MPEG-4 files.
- Verify vendor or distribution advisory status for deployed packages.
- Confirm compensating isolation controls on media processing systems.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-680: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-21844 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
8.8HighVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://talosintelligence.com/vulnerability_reports/TALOS-2021-1297CVE reference · x_refsource_MISC
- DSA-4966CVE reference · vendor-advisory, x_refsource_DEBIAN
- https://www.talosintelligence.com/vulnerability_reports/TALOS-2021-1297CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Integer Overflow to Buffer Overflow
Integer Overflow to Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.