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CVE Record

CVE-2021-39579: An issue was discovered in swftools through 20200710.

An issue was discovered in swftools through 20200710. A heap-buffer-overflow exists in the function string_hash() located in q.c. It allows an attacker to cause code Execution.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

SWFTools through 20200710 has a heap buffer overflow in string_hash() in q.c. If a user or automated service processes malicious input, an attacker may trigger code execution. The public record does not include CVSS, patch details, or confirmed exploitation, so urgency depends on whether SWFTools handles untrusted files.

Executive priority

Treat this as a targeted remediation item if SWFTools is used in file conversion or content-processing workflows. Business urgency is lower where the tool is absent or only used on trusted local files, but code execution potential warrants prompt inventory and containment.

Technical view

CVE-2021-39579 describes a heap-buffer-overflow in string_hash() in q.c in SWFTools through 20200710. The CVE states it allows code execution. The bundle does not provide exploit prerequisites, affected CPEs, CWE, CVSS, fixed version, or vendor remediation detail.

Likely exposure

Exposure is most plausible where SWFTools is installed on workstations, build systems, document conversion services, or web pipelines that process SWF-related or user-supplied files. The source bundle does not identify packaged distributions, CPEs, or downstream products.

Exploitation context

The bundle does not show CISA KEV listing or other evidence of active exploitation. Risk comes from potential code execution during file processing, especially if SWFTools runs automatically or with elevated privileges on untrusted content.

Researcher notes

Evidence is sparse. The CVE record points to a GitHub issue and states code execution, but lacks CVSS, CWE, CPEs, exploit prerequisites, and a named fix. Avoid assuming exploitability beyond the documented heap overflow and code execution claim.

Mitigation direction

  • Inventory systems for SWFTools through 20200710.
  • Check upstream project guidance and distribution advisories for fixed versions.
  • Avoid processing untrusted files with SWFTools until remediated.
  • Run SWFTools with least privilege and isolation where removal is not feasible.
  • Limit automated conversion workflows to trusted inputs only.

Validation and detection

  • Confirm installed SWFTools versions on servers, workstations, and CI images.
  • Identify workflows that pass user-supplied files to SWFTools.
  • Review package manager and vendor advisories for available updates.
  • Verify SWFTools processes run without elevated privileges.
  • Document compensating controls for any remaining installations.
Prepared
Confidence
medium
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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

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description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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CVE-2021-39579 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

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.

0CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.