CVE-2026-55738: CWE-121 Stack-based Buffer Overflow in rxi microtar
A stack-based buffer overflow vulnerability exists in rxi microtar version 0.1.0 within the raw_to_header() function. This occurs because the function uses strcpy() to copy fixed-width TAR header fields without ensuring null termination, allowing crafted TAR archives to trigger out-of-bounds reads and writes. Exploitation can lead to denial of service or potentially arbitrary code execution when parsing malicious archives.
AI Analysis
Technical Summary
CVE-2026-55738 is a stack-based buffer overflow in rxi microtar 0.1.0's raw_to_header() function. The vulnerability arises from using strcpy() to copy the 100-byte name and linkname fields of a TAR header without guaranteeing null termination. The POSIX ustar format allows these fields to be fully populated with non-null bytes, enabling a crafted TAR archive to cause strcpy() to read beyond the 512-byte raw header buffer on the stack and write past the destination buffer. This can be triggered remotely by supplying a malicious TAR archive that is opened or parsed via mtar_open(), mtar_read_header(), or mtar_find(), potentially causing a crash or arbitrary code execution. The issue was confirmed using AddressSanitizer.
Potential Impact
Successful exploitation allows a remote attacker to cause a stack-based buffer overflow leading to denial of service (application crash) or potentially arbitrary code execution when a crafted TAR archive is processed by the vulnerable functions in microtar 0.1.0.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid opening or parsing untrusted TAR archives with microtar 0.1.0. Monitor vendor channels for updates or patches addressing this vulnerability.
CVE-2026-55738: CWE-121 Stack-based Buffer Overflow in rxi microtar
Description
A stack-based buffer overflow vulnerability exists in rxi microtar version 0.1.0 within the raw_to_header() function. This occurs because the function uses strcpy() to copy fixed-width TAR header fields without ensuring null termination, allowing crafted TAR archives to trigger out-of-bounds reads and writes. Exploitation can lead to denial of service or potentially arbitrary code execution when parsing malicious archives.
CVSS v3.1
Score 8.8high
Affected software
Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-55738 is a stack-based buffer overflow in rxi microtar 0.1.0's raw_to_header() function. The vulnerability arises from using strcpy() to copy the 100-byte name and linkname fields of a TAR header without guaranteeing null termination. The POSIX ustar format allows these fields to be fully populated with non-null bytes, enabling a crafted TAR archive to cause strcpy() to read beyond the 512-byte raw header buffer on the stack and write past the destination buffer. This can be triggered remotely by supplying a malicious TAR archive that is opened or parsed via mtar_open(), mtar_read_header(), or mtar_find(), potentially causing a crash or arbitrary code execution. The issue was confirmed using AddressSanitizer.
Potential Impact
Successful exploitation allows a remote attacker to cause a stack-based buffer overflow leading to denial of service (application crash) or potentially arbitrary code execution when a crafted TAR archive is processed by the vulnerable functions in microtar 0.1.0.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid opening or parsing untrusted TAR archives with microtar 0.1.0. Monitor vendor channels for updates or patches addressing this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- TuranSec
- Date Reserved
- 2026-06-17T12:59:17.620Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a32a8a90b89be68886361c0
Added to database: 6/17/2026, 2:01:13 PM
Last enriched: 6/17/2026, 2:15:08 PM
Last updated: 6/17/2026, 2:58:18 PM
Views: 4
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.