Stack-based Buffer Overflow in Microtar by rxi
CVE-2026-43623

8.7HIGH

Key Information:

Vendor

Rxi

Status
Microtar
Vendor
CVE Published:
1 June 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-43623?

Microtar, up to version 0.1.0, is affected by a stack-based buffer overflow vulnerability in the raw_to_header() function located in src/microtar.c. This flaw arises when a specially crafted TAR archive is processed, where name or linkname fields are not properly null-terminated. The use of strcpy() to copy the associated fields can lead to excessive writes into a fixed-size buffer, potentially corrupting adjacent stack memory during the execution of functions such as mtar_open(), mtar_find(), or mtar_read_header(). Attackers could exploit this vulnerability by supplying malicious TAR files, causing unforeseen behavior and compromising system integrity.

Affected Version(s)

microtar 0 <= 0.1.0

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-43623 - Proof of Concept

References

https://github.com/rxi/microtar/issues/28
technical-descriptionexploit
https://github.com/rxi/microtar/issues/29
issue-tracking
https://github.com/rxi/microtar/issues/30
issue-tracking

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Byambadalai Sumiya (@ByamB4)
Saidakbarxon Maxsudxonov
mms (@3291710458)
.