Security readout for executives and security teams
Plain-English summary
This flaw affects older Adobe Acrobat Reader DC versions. A malicious PDF could make the application read memory it should not, exposing limited information from the current user context. It requires someone to open a malicious file, and the provided sources do not show active exploitation.
Executive priority
Handle through normal patch management. The business risk is limited information disclosure and depends on social engineering, but broad desktop exposure can still make remediation worthwhile.
Technical view
CVE-2021-35988 is a CWE-125 out-of-bounds read in Acrobat Reader DC. CVSS 3.1 is 3.3 with local attack vector, low complexity, no privileges, required user interaction, and low confidentiality impact only. Integrity and availability are not impacted by the provided record.
Likely exposure
Exposure is mainly user workstations, VDI images, and managed endpoints running Acrobat Reader DC at or below the affected 2021, 2020, or 2017 version thresholds.
Exploitation context
The record says exploitation requires user interaction: a victim must open a malicious file. The CVE is not listed as KEV in the supplied bundle, so active exploitation is not established here.
Researcher notes
The supplied evidence identifies affected version ceilings and impact, but not exploit details or fixed build numbers. Treat remediation validation as version and vendor-advisory confirmation, not exploit reproduction.
Mitigation direction
- Inventory Acrobat Reader DC versions across endpoints.
- Follow Adobe APSB21-51 guidance for the appropriate update path.
- Prioritize users who regularly handle external PDFs.
- Keep email and web controls for untrusted attachments enforced.
- Retire unsupported Acrobat Reader tracks where practical.
Validation and detection
- Compare installed versions against the affected version thresholds in the CVE record.
- Confirm Adobe APSB21-51 remediation guidance was applied to managed endpoints.
- Check software inventory for legacy 2017, 2020, and 2021 Reader DC installs.
- Verify endpoint controls warn or block untrusted PDF attachments.
- Record any exceptions with owner, business reason, and review date.
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-2021-35988 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/acrobat/apsb21-51.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.
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.