Security readout for executives and security teams
Plain-English summary
A crafted M4A audio file can trigger memory corruption in Adobe After Effects 18.4 and earlier. If a user opens the malicious file, attacker-controlled code could run with that user's privileges. This is mainly a workstation and creative-production risk, not a network-reachable server issue.
Executive priority
Treat this as a high-priority desktop application patch for creative and marketing teams. Business risk is highest where staff routinely handle client, vendor, or public media files.
Technical view
CVE-2021-40751 is a CWE-788 memory corruption issue in After Effects M4A parsing. CVSS 3.0 is 7.8: local attack vector, low complexity, no privileges required, user interaction required, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is likely limited to endpoints running Adobe After Effects 18.4 or earlier, especially users who import or open externally supplied media files.
Exploitation context
The provided sources say exploitation requires opening a specially crafted .m4a file. The CVE is not listed as CISA KEV, and no active exploitation evidence is provided.
Researcher notes
Evidence supports arbitrary code execution through malicious M4A parsing with user interaction. Sources do not provide exploit-in-the-wild evidence, weaponization details, or a fixed version in the supplied bundle, so remediation should follow Adobe's advisory.
Mitigation direction
- Inventory endpoints for Adobe After Effects 18.4 or earlier.
- Review Adobe APSB21-79 for the vendor-approved fixed version or update path.
- Prioritize updates for creative teams handling external media.
- Restrict opening untrusted .m4a files until updated.
- Use least-privilege user accounts for media production workstations.
Validation and detection
- Confirm installed After Effects versions on managed endpoints.
- Verify whether Adobe APSB21-79 remediation has been applied.
- Identify workflows that receive .m4a files from external parties.
- Review endpoint alerts involving After Effects process anomalies.
- Check exception lists for unmanaged creative workstations.
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-788: 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-40751 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
- 7.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:L/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:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
7.8HighVector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://helpx.adobe.com/security/products/after_effects/apsb21-79.htmlCVE 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.
Access of Memory Location After End of Buffer
Access of Memory Location After End of Buffer represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.