Security readout for executives and security teams
Plain-English summary
CVE-2021-39583 is a denial-of-service flaw in swftools through 20200710. A crafted input can trigger a NULL pointer dereference and crash the affected process. The available sources do not provide a CVSS score, patch version, or evidence of active exploitation.
Executive priority
Treat this as a reliability risk for services that rely on swftools processing untrusted input. Prioritize inventory and containment before broad emergency action, because available evidence shows denial of service only and no confirmed active exploitation.
Technical view
The issue is a NULL pointer dereference in pool_lookup_string2() in pool.c in swftools through 20200710. The CVE description states an attacker can cause denial of service. No CWE, CVSS vector, fixed version, or affected CPE list is provided in the source bundle.
Likely exposure
Exposure is most relevant where swftools through 20200710 is installed and processes untrusted or externally supplied conversion inputs. The source bundle does not identify downstream products, package names, or specific deployment patterns.
Exploitation context
The CVE is not listed as KEV, and the provided sources do not state active exploitation in the wild. A public GitHub issue is referenced, but the bundle only supports denial-of-service impact, not code execution or data theft.
Researcher notes
The public record is sparse: no CVSS, CWE, CPE, or fixed version is supplied. Analysis should stay limited to NULL dereference DoS in pool_lookup_string2() unless additional maintainer advisories or package changelogs confirm more detail.
Mitigation direction
- Inventory systems and containers for swftools through 20200710.
- Check the upstream GitHub issue and project guidance for a fixed release or workaround.
- Avoid processing untrusted files with vulnerable swftools until vendor guidance is confirmed.
- Isolate conversion workloads to limit service impact from crashes.
- Monitor process crashes in workflows that invoke swftools.
Validation and detection
- Confirm the installed swftools version on relevant hosts and build images.
- Identify services, scripts, or jobs that pass external input to swftools.
- Review crash logs for failures around swftools processing paths.
- Track the referenced GitHub issue for maintainer confirmation of remediation status.
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-2021-39583 mapping review
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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/136CVE 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.