CVE-2026-54417 PUBLISHED

An integer overflow in the mtar_next() function in src/microtar.c in rxi microtar 0.1.0 allows a remote attacker to cause a denial of service (uncontrolled CPU consumption / infinite loop) via a crafted tar archive. mtar_next() computes the offset to the next record as round_up(h.size, 512) + sizeof(mtar_raw_header_t) using 32-bit arithmetic. When the header size field is a multiple of 512 in the range 0xFFFFFC01-0xFFFFFE00 (e.g. 0xFFFFFE00), the addition wraps to 0, so mtar_next() seeks to the current record position instead of advancing. As a result, mtar_find() and any loop that iterates entries with mtar_next() repeat indefinitely over the same record, hanging the process at 100% CPU with no recovery.

• Saidakbarxon Maxsudxonov reporter

• https://github.com/rxi/microtar/blob/master/src/microtar.c#L239
• https://github.com/rxi/microtar
• Vulnerable source code: src/microtar.c (mtar_next)

• CWE-190 Integer Overflow or Wraparound CWE
• CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop') CWE