Security readout for executives and security teams
Plain-English summary
This flaw affects Adobe Media Encoder when a user opens a malicious MP4 file. It can expose sensitive memory and may help an attacker bypass defenses such as ASLR. It is low severity because exploitation is local, requires user interaction, and only affects confidentiality.
Executive priority
Treat as a low-priority patching item unless media teams routinely process untrusted MP4s. It is unlikely to cause direct system compromise alone, but memory disclosure can support chained attacks.
Technical view
CVE-2021-43758 is a CWE-125 out-of-bounds read in Adobe Media Encoder MP4 parsing. A crafted MP4 can trigger memory disclosure. The CVSS 3.1 score is 3.3 with AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N.
Likely exposure
Exposure is most likely on workstations running Adobe Media Encoder 22.0, 15.4.2, or earlier, especially users who handle untrusted MP4 files from email, uploads, clients, or shared storage.
Exploitation context
The provided sources do not show active exploitation, and the CVE is not listed as KEV. Exploitation requires the victim to open a malicious MP4 file locally, limiting scale but still relevant for creative and media-processing teams.
Researcher notes
Evidence supports an MP4 parsing out-of-bounds read with confidentiality impact only. No exploit details, public exploitation, or specific fixed version evidence is present in the supplied bundle beyond the Adobe advisory reference.
Mitigation direction
- Inventory Adobe Media Encoder installations and identify affected versions.
- Follow Adobe APSB21-118 for vendor-approved update or remediation guidance.
- Prioritize systems used to open external or client-supplied MP4 files.
- Discourage opening untrusted MP4 files outside approved workflows.
- Use sandboxed media-review workflows for suspicious or unsolicited files.
Validation and detection
- Confirm installed Adobe Media Encoder versions against 22.0, 15.4.2, and earlier.
- Check Adobe APSB21-118 for the applicable fixed release guidance.
- Review endpoint telemetry for unexpected crashes while opening MP4 files.
- Review mail and file-transfer controls for suspicious MP4 delivery paths.
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-125: 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-2021-43758 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.