Security readout for executives and security teams
Plain-English summary
A malicious MPEG-4 video can trigger memory corruption in vulnerable GPAC decoding code. Successful exploitation could let an attacker compromise confidentiality, integrity, and availability, but the source bundle says user interaction is required: someone or some service must open or process the crafted video.
Executive priority
Treat this as a high-priority patching and exposure-review item for any business process handling external video files. Urgency is highest for automated media processing and staff likely to receive or open untrusted videos.
Technical view
CVE-2021-21860 is an integer truncation in GPAC Project Advanced Content MPEG-4 decoding. Parsing FOURCC 'trik' can cause improper memory allocation and a heap-based buffer overflow. The listed affected versions are GPAC Advanced Content v1.0.1 and commit a8a8d412dabcb129e695c3e7d861fcc81f608304.
Likely exposure
Exposure is most likely where GPAC or applications embedding GPAC decode MPEG-4 content from users, partners, email attachments, uploads, or automated media pipelines. Desktop media workflows and server-side transcoding or inspection services should be checked first.
Exploitation context
The source bundle states exploitation requires a specially crafted MPEG-4 and convincing a user to open it. KEV is false, and the provided sources do not confirm active exploitation in the wild.
Researcher notes
Focus analysis on CWE-680 integer overflow-to-buffer-overflow behavior in MPEG-4 'trik' parsing. The bundle provides affected build identifiers and impact, but not full fixed-version details beyond the Debian advisory reference.
Mitigation direction
- Apply GPAC or distribution security updates from official vendor guidance.
- Use Debian DSA-4966 guidance where Debian packages are in scope.
- Avoid processing untrusted MPEG-4 files on vulnerable GPAC builds.
- Sandbox or isolate media decoding workflows handling external content.
- Limit upload-based media processing until patched and validated.
Validation and detection
- Inventory GPAC, libgpac, and applications embedding GPAC decoding functionality.
- Check for GPAC Advanced Content v1.0.1 or the listed commit.
- Identify workflows that open or process externally supplied MPEG-4 files.
- Confirm patched packages or vendor-fixed builds are deployed.
- Review media processing isolation and crash monitoring coverage.
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-2021-21860 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-2021-1298CVE reference · x_refsource_MISC
- DSA-4966CVE reference · vendor-advisory, x_refsource_DEBIAN
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.