Quick answers
- Is CVE-2026-43623 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-43623 being exploited in the wild.
- How severe is CVE-2026-43623?
- High severity, with a CVSS score of 8.8, published 1 June 2026.
- Which products and versions are affected?
- Rxi Microtar through 0.1.0.
- Is there a fix for CVE-2026-43623?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-43623 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-43623?
- Check whether you run Rxi Microtar at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A stack-based buffer overflow exists in microtar through 0.1.0 within the raw_to_header() function in src/microtar.c. The vulnerability stems from the use of strcpy() to copy 100-byte fixed-width fields (name and linkname) from the raw TAR header into the mtar_header_t struct. Because the POSIX TAR format allows these fields to be non-null-terminated if they occupy the full 100 bytes, strcpy() continues reading into adjacent memory, resulting in a write of up to 355 bytes into a 100-byte destination buffer. An attacker can exploit this by providing a malformed TAR archive to functions like mtar_open(), mtar_find(), or mtar_read_header(), potentially leading to arbitrary code execution. As of the advisory date, the library remains unpatched, though developers are advised to replace strcpy() with bounded memcpy() calls.
Affected products
- rxi microtar through 0.1.0
Timeline
- 2026-02-16: disclosed: Initial vulnerability report on GitHub (Issue #28)
- 2026-06-01: advisory: CVE-2026-43623 published by VulnCheck/NVD