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CVE Record

CVE-2021-42201: An issue was discovered in swftools through 20201222.

An issue was discovered in swftools through 20201222. A heap-buffer-overflow exists in the function swf_GetD64() located in rfxswf.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

CVE-2021-42201 is a memory corruption flaw in swftools through 20201222. If a system uses swftools to process attacker-supplied SWF files, the issue is reported to allow code execution. The public record does not provide CVSS scoring, confirmed affected package metadata, or a named fixed release.

Executive priority

Treat this as high priority if swftools processes external files. The business risk is code execution through legacy Flash tooling, but urgency is lower where swftools is absent or only handles trusted internal files.

Technical view

The CVE describes a heap-buffer-overflow in swftools function swf_GetD64() in rfxswf.c. The stated impact is possible code execution. Source data is sparse: affected vendor/product fields are not populated, CVSS and CWE are absent, and the only linked technical reference is a GitHub issue.

Likely exposure

Exposure is most likely where swftools is installed and used to parse or convert SWF content, especially automated pipelines handling untrusted files. The bundle only names swftools through 20201222 and does not identify downstream distributions or packaged versions.

Exploitation context

CISA KEV is false in the provided bundle, and no cited source confirms active exploitation. Risk depends on whether an attacker can cause a vulnerable swftools process to open a crafted SWF file.

Researcher notes

Evidence is limited to the CVE description and one GitHub issue reference. Do not assume a specific fixed version, exploit availability, or affected package ecosystem from this bundle alone. Focus validation on reachable SWF parsing paths and privilege boundaries around swftools.

Mitigation direction

  • Inventory systems and containers for swftools installations.
  • Avoid processing untrusted SWF files with swftools.
  • Sandbox or isolate any required SWF processing workflows.
  • Check upstream issue and vendor/package guidance for fixed builds.
  • Remove swftools where business use is no longer required.

Validation and detection

  • Confirm whether swftools is installed in production, CI, or content pipelines.
  • Record installed version or build date and compare with 20201222.
  • Identify workflows that accept SWF files from users or third parties.
  • Review package manager, container, and build manifests for swftools.
  • Track the linked GitHub issue for patch or maintainer guidance.
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 · low confidence lookup

CVE-2021-42201 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.