Security readout for executives and security teams
Plain-English summary
Yasm 1.3.0 can crash when processing certain NASM preprocessor input because of a NULL pointer dereference. The public record does not show active exploitation, a CVSS score, or a named vendor fix. Business impact is most plausible where Yasm processes untrusted files in build, packaging, or CI workflows.
Executive priority
Handle as a targeted build-tool resilience issue, not an internet-wide emergency. Prioritize if Yasm is used in services that process untrusted code submissions or third-party source packages.
Technical view
CVE-2021-33466 is a NULL pointer dereference in expand_smacro() in modules/preprocs/nasm/nasm-pp.c in Yasm 1.3.0. Based on the supplied sources, the known impact is process crash or denial of service during input handling. Evidence is insufficient for code execution, privilege escalation, or confirmed remediation details.
Likely exposure
Exposure is likely limited to systems using Yasm 1.3.0, especially automated build services, CI runners, package builders, or analysis pipelines that accept external assembly source or project submissions.
Exploitation context
The sources reference a public GitHub issue and proof material, but the CVE bundle does not report KEV listing or active exploitation. Treat this as a crashable parser/preprocessor issue unless new vendor or threat-intelligence evidence says otherwise.
Researcher notes
The available record names the vulnerable function and file but lacks CVSS, CWE, detailed affected CPEs, and fix status. Avoid assuming broader Yasm versions or downstream packages are affected without direct evidence.
Mitigation direction
- Inventory systems and containers for Yasm 1.3.0.
- Check the Yasm project for maintainer guidance or patched releases.
- Restrict Yasm processing to trusted source inputs where possible.
- Run build jobs handling external submissions in isolated environments.
- Monitor CI and package build systems for unexpected Yasm crashes.
Validation and detection
- Confirm whether Yasm 1.3.0 is installed or bundled.
- Identify workflows that invoke Yasm on externally supplied files.
- Review build logs for repeatable Yasm crashes or abnormal termination.
- Check dependency manifests and base images for Yasm inclusion.
- Track the referenced GitHub issue for fix or status updates.
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-2021-33466 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
- 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/yasm/yasm/issues/172CVE reference · x_refsource_MISC
- https://gist.github.com/Clingto/bb632c0c463f4b2c97e4f65f751c5e6dCVE 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.