Security readout for executives and security teams
Plain-English summary
CVE-2021-31240 affects libming v0.4.8, a library used for SWF/Flash parsing. The reported issue can let a local attacker execute arbitrary code through SWF import-asset parsing. Business urgency is highest where legacy SWF processing still exists on workstations, build systems, or internal services.
Executive priority
Prioritize remediation if the organization still processes SWF files or includes libming in internal tooling. The risk is high impact but appears local and dependency-specific based on current evidence.
Technical view
The CVE describes arbitrary code execution in libming v0.4.8 via parseSWF_IMPORTASSETS in parser.c. The CVSS vector is local, low complexity, low privileges, no user interaction, with high confidentiality, integrity, and availability impact. The bundle lists CWE-401 but provides limited technical detail.
Likely exposure
Exposure is likely limited to systems that have libming v0.4.8 installed and parse SWF files. The provided affected-product fields are not populated, so confirm through local package inventory, SBOMs, and source dependencies.
Exploitation context
No active exploitation is stated in the provided sources, and KEV is false. The CVSS vector indicates local access with low privileges is required, not network-only exploitation. Treat untrusted SWF parsing as the main risk context.
Researcher notes
The source bundle is sparse: it identifies the function, version, CVSS vector, and CWE, but does not include a patch reference, detailed root cause, or confirmed exploit activity. Avoid broad product claims until dependency evidence is collected.
Mitigation direction
- Inventory systems and applications using libming v0.4.8.
- Avoid processing untrusted SWF files with affected libming builds.
- Check libming or downstream vendor guidance for a supported fix.
- Run any required SWF parsing with least privilege and isolation.
- Retire legacy SWF workflows where business use no longer exists.
Validation and detection
- Check SBOMs, package manifests, and binaries for libming v0.4.8.
- Identify jobs, services, or tools that parse SWF content.
- Confirm SWF parsing is not exposed to untrusted local users.
- Verify parser processes run with restricted privileges.
- Track the referenced GitHub issue for fix or maintainer guidance.
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.
CWE-401: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution 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.
Open ATT&CK lookupCVE-2021-31240 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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 vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/libming/libming/issues/218CVE reference
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.
Missing Release of Memory after Effective Lifetime
Missing Release of Memory after Effective Lifetime represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.