Security readout for executives and security teams
Plain-English summary
Yasm 1.3.0 has a bug that can crash the assembler when processing certain NASM-style macro input. Business impact is most relevant where automated build or analysis systems compile untrusted or third-party assembly source. The public data does not provide CVSS, affected downstream packages, or vendor fix details.
Executive priority
Treat this as a targeted reliability and build-chain risk, not a confirmed widespread emergency. Prioritize environments that process untrusted source code automatically, then wait for or confirm vendor-maintainer remediation guidance.
Technical view
CVE-2021-33465 is a NULL pointer dereference in expand_mmacro() in modules/preprocs/nasm/nasm-pp.c in yasm 1.3.0. The record identifies the flaw and public references, but provides no CVSS vector, CWE, patch commit, or supported affected CPE data.
Likely exposure
Exposure is likely limited to systems that have yasm 1.3.0 installed and use it to process NASM preprocessor input, especially CI, package-build, or malware-analysis workflows handling external source. The bundle does not identify operating system distributions or bundled products.
Exploitation context
The bundle does not report active exploitation and KEV is false. Public references include a GitHub issue and a gist, suggesting public technical disclosure, but the supplied evidence does not establish weaponized exploitation or real-world abuse.
Researcher notes
The evidence supports a NULL pointer dereference in one function and version only. The bundle lacks CVSS, CWE, fixed-version, exploitability, and downstream product mapping. Avoid extrapolating beyond yasm 1.3.0 without additional vendor or distribution data.
Mitigation direction
- Inventory systems and build images for yasm version 1.3.0.
- Check Yasm project or distribution maintainer guidance for fixed packages.
- Avoid processing untrusted assembly input with affected yasm builds.
- Isolate build or analysis jobs that must run yasm on external source.
Validation and detection
- Confirm installed yasm versions on developer, CI, and build hosts.
- Review build pipelines for NASM/Yasm preprocessing of external source.
- Check whether package managers provide a patched yasm build.
- Monitor the linked Yasm issue for remediation details.
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-2021-33465 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/173CVE 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.