Security readout for executives and security teams
Plain-English summary
CVE-2021-33467 is a memory-safety flaw in Yasm 1.3.0. The assembler can use memory after it has been freed while handling NASM-style preprocessing. Business risk depends on whether Yasm processes untrusted source files in build, analysis, or packaging workflows.
Executive priority
Handle as a targeted build-tool exposure review, not an emergency internet-facing incident. Prioritize environments that compile untrusted inputs or support customer-supplied code. Urgency increases if vendor guidance confirms code execution impact or broader affected versions.
Technical view
The CVE describes a use-after-free in pp_getline() within modules/preprocs/nasm/nasm-pp.c in Yasm 1.3.0. The public record provides no CVSS score, CWE, confirmed impact, fixed version, or vendor mitigation. Treat impact as uncertain until vendor or maintainer guidance is confirmed.
Likely exposure
Exposure is most likely in development, CI, packaging, or reverse-engineering environments that run Yasm 1.3.0 against untrusted or externally supplied assembly input. The source bundle does not identify other affected versions or downstream products.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. Public references exist on GitHub and Gist, but the provided data does not establish in-the-wild use, exploit maturity, or confirmed remote code execution.
Researcher notes
The public CVE data is sparse. It names Yasm 1.3.0 and the affected function/file, but omits CVSS, CWE, affected CPEs, patch status, and impact details. Avoid assuming exploitability beyond the stated use-after-free.
Mitigation direction
- Inventory systems and pipelines using Yasm, especially version 1.3.0.
- Check the Yasm issue for maintainer guidance or fixed release information.
- Upgrade or replace Yasm if a maintained fixed version is available.
- Restrict Yasm from processing untrusted assembly input where practical.
- Run Yasm in isolated build environments for untrusted inputs.
Validation and detection
- Confirm installed Yasm versions through package inventories or build images.
- Identify CI jobs or tools that invoke Yasm on external input.
- Review whether NASM preprocessing paths are used in affected workflows.
- Check vendor and project references for fix status before closure.
- Monitor crashes or sanitizer findings involving nasm-pp.c pp_getline().
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-2021-33467 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/163CVE 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.