Security readout for executives and security teams
Plain-English summary
CVE-2021-39596 is a denial-of-service flaw in swftools through 20200710. A crash can occur because code_parse() in code.c dereferences a NULL pointer. Business impact is service interruption where swftools processes untrusted content.
Executive priority
Prioritize based on whether swftools touches untrusted files in production. Internet-facing or customer-upload processing paths merit near-term containment; internal-only legacy use is lower urgency but should still be inventoried.
Technical view
The CVE record describes a NULL pointer dereference in swftools code_parse(), located in code.c. The documented security effect is denial of service. No CVSS score, CWE, concrete affected package metadata, patch version, or active exploitation evidence is provided in the supplied sources.
Likely exposure
Exposure is most likely where swftools through 20200710 is installed or embedded in file conversion, media processing, or legacy Flash workflows. The source bundle does not identify downstream distributions, CPEs, or hosted services.
Exploitation context
The supplied sources support denial-of-service impact only. CISA KEV is false, and no cited source states active exploitation. Treat exploitability details as incomplete and avoid assuming remote exposure unless swftools processes attacker-controlled input.
Researcher notes
The record is sparse: no CVSS vector, CWE mapping, CPEs, fixed release, or detailed proof is included in the source bundle. Analysis should stay limited to NULL dereference denial of service in swftools through 20200710.
Mitigation direction
- Check upstream issue and downstream package advisories for maintained fixes.
- Inventory systems and containers for swftools through 20200710.
- Avoid processing untrusted SWF or Flash-derived files with affected builds.
- Run conversion workloads with process isolation and resource limits.
- Replace swftools where no maintained fix is available.
Validation and detection
- Confirm installed swftools versions against the 20200710 affected boundary.
- Identify services, jobs, or pipelines that invoke swftools.
- Review whether any workflow accepts external or user-supplied files.
- Check operational logs for repeated swftools crashes or worker restarts.
- Track vendor or distributor advisories for patch confirmation.
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-2021-39596 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/matthiaskramm/swftools/issues/146CVE 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.