{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-55738: Stack Buffer Overflow in rxi/microtar raw_to_header() via non-null-terminated TAR name field","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-55738","status":"final","version":"1","initial_release_date":"2026-06-17T13:45:00.399Z","current_release_date":"2026-06-17T15:00:58.607Z","revision_history":[{"date":"2026-06-17T13:45:00.399Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"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.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-55738 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-55738"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-55738"},{"category":"external","summary":"github.com","url":"https://github.com/rxi/microtar/blob/master/src/microtar.c#L111"},{"category":"external","summary":"github.com","url":"https://github.com/rxi/microtar"},{"category":"external","summary":"Vulnerable source code: src/microtar.c (raw_to_header)","url":"https://raw.githubusercontent.com/rxi/microtar/master/src/microtar.c"}]},"product_tree":{"branches":[{"category":"vendor","name":"rxi","branches":[{"category":"product_name","name":"microtar","branches":[{"category":"product_version","name":"0.1.0","product":{"name":"rxi microtar 0.1.0","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:rxi:microtar:0.1.0:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-55738","title":"Stack Buffer Overflow in rxi/microtar raw_to_header() via non-null-terminated TAR name field","notes":[{"category":"description","text":"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.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v4":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","baseScore":8.7,"baseSeverity":"HIGH"},"products":["CSAFPID-1"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1"]}]}]}