Buffer overflow in Rxi Microtar
CVE-2026-43623
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.005 (42.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 42.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.005 · change: -0.001
Affected products
- Rxi Microtar — versions 0
Weakness classification (CWE)
References
- github.com/rxi/microtar/issues/28 (issue-tracking, technical-description, exploit)
- github.com/rxi/microtar/issues/29 (issue-tracking)
- github.com/rxi/microtar/issues/30 (issue-tracking)
- www.vulncheck.com/advisories/microtar-stack-based-buffer-overflow-via-raw-to-he… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-43623?
- CVE-2026-43623 is a high-severity vulnerability in Rxi Microtar, classified under Stack-based Buffer Overflow. CVSS score: 8.8/10. Published 2026-06-01.
- How severe is CVE-2026-43623?
- High severity. CVSS v3 base score is 8.8 out of 10.