Security readout for executives and security teams
Plain-English summary
CVE-2021-39543 is an availability issue in pdftools through 20200714. A malformed or hostile PDF could crash the affected PDF analysis code, causing denial of service. The source bundle does not provide CVSS, a fixed version, or evidence of active exploitation.
Executive priority
Treat this as a targeted availability risk. Prioritize if pdftools is used in customer-facing upload, document intake, email, or security automation paths. If use is internal and trusted-only, handle through normal maintenance while tracking vendor guidance.
Technical view
A NULL pointer dereference exists in Analyze::AnalyzeRoot() in analyze.cpp in pdftools through 20200714. The documented impact is denial of service. The bundle lists no CWE, CVSS vector, patch reference, or precise product metadata beyond pdftools and the version cutoff.
Likely exposure
Exposure is most likely where pdftools through 20200714 processes PDFs supplied by users, customers, email, web uploads, or automated ingestion jobs. Internal-only tooling that never handles untrusted PDFs has lower practical exposure.
Exploitation context
The provided sources support a crash-based denial-of-service condition, not code execution. There is no KEV listing and no cited evidence of active exploitation in the bundle. Exploitability details are limited to the affected function and DoS outcome.
Researcher notes
Evidence is sparse. The CVE names the vulnerable function and version range but omits CVSS, CWE, vendor metadata, and patch status. Avoid expanding impact beyond denial of service unless additional primary sources establish it.
Mitigation direction
- Inventory systems using pdftools through 20200714.
- Check the GitHub issue and vendor guidance for fixes or maintained replacements.
- Avoid processing untrusted PDFs with affected versions until remediated.
- Run PDF processing in isolated workers with restart and resource limits.
- Monitor PDF analysis crashes and ingestion failure spikes.
Validation and detection
- Confirm installed pdftools version and source repository lineage.
- Map every workflow that sends PDFs to pdftools.
- Review crash logs for AnalyzeRoot or PDF parsing failures.
- Verify whether any updated or patched version is available from project sources.
- Test remediation in a controlled environment before restoring untrusted input handling.
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.
CVE-2021-39543 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/leonhad/pdftools/issues/1CVE 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.