Security readout for executives and security teams
Plain-English summary
Adobe Media Encoder can read memory outside the expected MP4 parsing boundary when a user opens a malicious MP4 file. The main business risk is limited information disclosure that may help bypass defenses like ASLR, not direct system takeover based on the provided sources.
Executive priority
Treat this as a low-priority patching item unless the organization regularly handles external MP4 media. Remediate through normal endpoint software maintenance, with faster action for creative or media teams exposed to untrusted files.
Technical view
CVE-2021-43759 is a CWE-125 out-of-bounds read in Adobe Media Encoder MP4 parsing. Affected versions are described as 22.0, 15.4.2, and earlier. CVSS 3.1 is 3.3, with local attack vector, required user interaction, low confidentiality impact, and no integrity or availability impact.
Likely exposure
Exposure is likely limited to workstations or media-processing systems running Adobe Media Encoder 22.0, 15.4.2, or earlier where users may open externally supplied MP4 files.
Exploitation context
The source bundle does not indicate active exploitation, and the CVE is not listed as KEV. Exploitation requires convincing a victim to open a malicious MP4 file in Adobe Media Encoder.
Researcher notes
Evidence supports an out-of-bounds read with potential sensitive memory disclosure and ASLR mitigation bypass. The provided affected data is imprecise, including a placeholder version entry, so fixed-version validation should come from Adobe APSB21-118.
Mitigation direction
- Review Adobe APSB21-118 for the fixed Media Encoder versions and update guidance.
- Prioritize upgrades on systems that process untrusted or externally supplied MP4 files.
- Limit opening MP4 files from unknown or untrusted sources until updated.
- Use endpoint controls to restrict risky file handling where business workflows allow.
Validation and detection
- Inventory installed Adobe Media Encoder versions across endpoints and media workstations.
- Flag systems running 22.0, 15.4.2, or earlier for remediation review.
- Confirm remediation against Adobe APSB21-118 rather than assuming a fixed version.
- Check mail, download, and ticket workflows where MP4 files reach Media Encoder users.
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
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ATT&CK lookup starting points
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CWE-125: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-43759 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
- Low
- CVSS
- 3.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
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:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N1.81.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
3.3LowVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://helpx.adobe.com/security/products/media-encoder/apsb21-118.htmlCVE reference · vendor-advisory
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.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.