rxi microtar 0.1.0 Tar src/microtar.c mtar_next integer overflow

Summaryinfo

A vulnerability classified as problematic has been found in rxi microtar 0.1.0. This issue affects the function mtar_next of the file src/microtar.c of the component Tar Handler. The manipulation leads to integer overflow. This vulnerability is referenced as CVE-2026-54417. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in rxi microtar 0.1.0. This issue affects the function mtar_next of the file src/microtar.c of the component Tar Handler. The manipulation with an unknown input leads to a integer overflow vulnerability. Using CWE to declare the problem leads to CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. Impacted is availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-54417 since 06/13/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 06/17/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• rxi

Name

• microtar

Version

• 0.1.0

Website

• Product: https://github.com/rxi/microtar/

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