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CVE Record

CVE-2021-39561: An issue was discovered in swftools through 20200710.

An issue was discovered in swftools through 20200710. A stack-buffer-overflow exists in the function Gfx::opSetFillColorN() located in Gfx.cc. 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-2021-39561 is a memory safety flaw in swftools through 20200710. If vulnerable swftools processes malicious input, the issue is reported to allow code execution. Business urgency depends on whether swftools handles untrusted files in production workflows.

Executive priority

Prioritize assessment if swftools processes external files in production. Treat internet-facing or customer-upload conversion workflows as higher risk because the CVE source states potential code execution, despite incomplete scoring and remediation details.

Technical view

The CVE describes a stack buffer overflow in Gfx::opSetFillColorN() in Gfx.cc in swftools through 20200710. The source record states the flaw can allow code execution, but provides no CVSS score, CWE mapping, CPEs, patch version, or exploit details.

Likely exposure

Exposure is most likely on systems running swftools through 20200710, especially automated conversion or processing paths that accept files from users, customers, partners, or the internet.

Exploitation context

The provided sources do not show CISA KEV listing or active exploitation. Exploitation would require vulnerable swftools to process malicious input reaching the affected color handling code path. Public evidence in the bundle is limited.

Researcher notes

The record is sparse: affected CPEs, CVSS, CWE, fixed version, and exploit status are absent from the provided bundle. Analysis should focus on confirming local swftools use, reachable input paths, and whether downstream distributors patched the Gfx.cc overflow.

Mitigation direction

  • Inventory swftools installations and versions across servers, containers, and build images.
  • Check upstream issue and package maintainer guidance for fixed releases or patches.
  • Avoid processing untrusted files with vulnerable swftools until guidance is confirmed.
  • Sandbox or isolate any required file-processing workflow that uses swftools.
  • Restrict file upload or conversion access to trusted sources where feasible.

Validation and detection

  • Confirm whether swftools is installed and whether version is through 20200710.
  • Map all workflows where swftools processes user-supplied or external files.
  • Review package changelogs or maintainer advisories for a CVE-2021-39561 fix reference.
  • Verify runtime isolation around any remaining swftools processing path.
  • Check vulnerability scanners for swftools findings, but validate manually due sparse CPE data.
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-2021-39561 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.