# CVE-2026-55738

## Summary

- **CVE ID:** CVE-2026-55738
- **Severity:** HIGH
- **CVSS Score:** 8.8 (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)
- **CWE:** CWE-121, CWE-170
- **Published:** Jun 17, 2026
- **Last Modified:** Aug 10, 2026

## Description

A stack-based buffer overflow exists in the raw_to_header() function in src/microtar.c in rxi microtar 0.1.0. The function copies the 100-byte name and linkname fields of a TAR header with strcpy() without guaranteeing null termination of the source. The POSIX ustar format permits these fixed-width fields to be fully populated with non-null bytes, so a crafted archive whose linkname field (followed by the trailing padding of the 512-byte raw header) contains no null terminator causes strcpy() to read past the end of the 512-byte raw header stack buffer and to write past the destination header buffer. A remote attacker who supplies a crafted TAR archive that the victim opens or parses (via mtar_open(), mtar_read_header(), or mtar_find()) can cause an out-of-bounds read and a stack buffer overflow, resulting in denial of service (crash) and potentially arbitrary code execution. Confirmed with AddressSanitizer: stack-buffer-overflow READ of size 356 in raw_to_header at src/microtar.c:112.

## Affected Products

- rxi — microtar (0.1.0)

## References

- [CNA](https://github.com/rxi/microtar/blob/master/src/microtar.c#L111)
- [CNA](https://github.com/rxi/microtar)
- [CNA](https://raw.githubusercontent.com/rxi/microtar/master/src/microtar.c)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.40%
- **EPSS Percentile:** 33.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._