Bug 2489845 (CVE-2026-55738)

Summary: CVE-2026-55738 microtar: microtar: Arbitrary code execution and denial of service via crafted TAR archive
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in microtar. A remote attacker can exploit a stack-based buffer overflow vulnerability in the raw_to_header() function by supplying a specially crafted TAR (Tape Archive) file. When the victim opens or parses this archive, the flaw can lead to an out-of-bounds read and a stack buffer overflow. This can result in a denial of service, causing the application to crash, and potentially allow for arbitrary code execution.
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Bug Depends On: 2490697, 2490698    
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Description OSIDB Bzimport 2026-06-17 15:01:44 UTC 
A stack-based buffer overflow exists in the raw_to_header() function in src/microtar.c in rxi microtar 0.1.0. The function copies the 100-byte name and linkname fields of a TAR header with strcpy() without guaranteeing null termination of the source. The POSIX ustar format permits these fixed-width fields to be fully populated with non-null bytes, so a crafted archive whose linkname field (followed by the trailing padding of the 512-byte raw header) contains no null terminator causes strcpy() to read past the end of the 512-byte raw header stack buffer and to write past the destination header buffer. A remote attacker who supplies a crafted TAR archive that the victim opens or parses (via mtar_open(), mtar_read_header(), or mtar_find()) can cause an out-of-bounds read and a stack buffer overflow, resulting in denial of service (crash) and potentially arbitrary code execution. Confirmed with AddressSanitizer: stack-buffer-overflow READ of size 356 in raw_to_header at src/microtar.c:112.