rxi microtar src/microtar.c mtar_write_file_header/mtar_write_dir_header Name stack-based overflow

Summaryinfo

A vulnerability classified as critical has been found in rxi microtar. This issue affects the function mtar_write_file_header/mtar_write_dir_header of the file src/microtar.c. This manipulation of the argument Name causes stack-based overflow. This vulnerability appears as CVE-2026-71267. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability has been found in rxi microtar (version now known) and classified as critical. Affected by this vulnerability is the function mtar_write_file_header/mtar_write_dir_header of the file src/microtar.c. The manipulation of the argument name with an unknown input leads to a stack-based overflow vulnerability. The CWE definition for the vulnerability is CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

microtar's mtar_write_file_header() and mtar_write_dir_header() functions (src/microtar.c) copy a caller-supplied entry name into the 100-byte `name` field of a stack-allocated mtar_header_t via strcpy(h.name, name), with no check that strlen(name) is less than 100 before the copy. Any application that calls these functions with an externally-influenced filename longer than 99 characters (e.g. when archiving user-supplied or attacker-controlled filenames) triggers a stack buffer overflow.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-71267 since 08/05/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. 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 08/05/2026).

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

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

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