Security readout for executives and security teams
Plain-English summary
CVE-2021-46700 describes a double-free memory error in libsixel 1.8.6. Business risk depends on whether your software uses libsixel’s encoder path. The public record does not provide severity scoring, known exploitation, or a named fixed version.
Executive priority
Treat this as a targeted inventory and remediation task, not an emergency, unless libsixel 1.8.6 handles untrusted input in a sensitive service. Escalate if vendor evidence shows exploitation or a high-impact fix.
Technical view
The issue is reported in sixel_encoder_output_without_macro, called from sixel_encoder_encode_frame in encoder.c. A double free may cause process instability and can indicate memory corruption risk, but the supplied CVE data lacks CVSS, CWE, CPE, and remediation details.
Likely exposure
Likely exposure is limited to systems, applications, or packages that include libsixel 1.8.6 and invoke the affected SIXEL encoder code path.
Exploitation context
The source bundle does not show active exploitation, and the CVE is not in KEV. A public GitHub issue is referenced, but exploitability and real-world abuse are not established in the provided sources.
Researcher notes
The public record is sparse: no CVSS, CWE, CPE, affected product list, or explicit patch is included. Focus analysis on local dependency presence, encoder reachability, input trust boundaries, and upstream issue history.
Mitigation direction
- Inventory applications and packages for libsixel 1.8.6.
- Check upstream libsixel and vendor advisories for fixed releases.
- Update or rebuild affected software when vendor guidance identifies a fix.
- Limit processing of untrusted SIXEL/image inputs where practical.
- Monitor affected services for crashes or allocator-related errors.
Validation and detection
- Check SBOMs, lockfiles, package metadata, and container images for libsixel.
- Confirm whether the application invokes libsixel encoder functionality.
- Review vendor package changelogs for CVE-2021-46700 references.
- Correlate crash logs with libsixel encoder stack traces.
- Document unresolved exposure where version or code path cannot be confirmed.
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-2021-46700 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/saitoha/libsixel/issues/158CVE 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.