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Stack-based Buffer OverflowWeakness · CWE-121

CVE-2026-43623

HIGH · 8.8 CVSS v3.1 Published 2026-06-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
microtar through 0.1.0 contains a stack-based buffer overflow vulnerability in the raw_to_header() function in src/microtar.c that allows attackers to corrupt adjacent stack memory by supplying a crafted TAR archive with non-null-terminated name or linkname fields. The function uses strcpy() to copy 100-byte ustar format fields that lack null terminators, causing writes of up to 355 bytes into a 100-byte destination buffer when mtar_open(), mtar_find(), or mtar_read_header() process attacker-supplied TAR archives.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

microtar through 0.1.0 has a stack-based buffer overflow in the raw_to_header() function in src/microtar.c. The vulnerability stems from using strcpy() to copy 100-byte ustar format fields (name, linkname) without ensuring null termination, allowing up to 355 bytes to be written into a 100-byte destination buffer when processing attacker-supplied TAR archives via mtar_open(), mtar_find(), or mtar_read_header().

MitigationReplace strcpy() calls with bounds-safe alternatives (strncpy, snprintf, or memcpy with explicit null termination) and add validation to ensure fields are properly null-terminated before copying. Audit all other file parsing functions in microtar.c for similar issues.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Locate microtar library in your environment
    Search for libmicrotar.so (Linux) or microtar.lib/microtar.dll (Windows), or check your dependency manifests/package files for microtar
    Affected if microtar library is present in your environment and version is 0.1.0 or earlier
  2. Determine installed microtar version
    Check the library filename for version info, examine headers (microtar.h) for version macros, or review dependency version strings in your build system
    Affected if Version is 0.1.0 or any version earlier than a patched release that addresses strcpy in raw_to_header()
  3. Identify if vulnerable functions process external input
    Audit code that calls mtar_open(), mtar_find(), or mtar_read_header() and determine whether the TAR archive paths/names come from untrusted sources (user upload, network, external storage)
    Affected if Your application calls any of these functions on TAR archives from untrusted or external sources
  4. Inspect source code for vulnerable strcpy pattern
    If you have access to microtar source, open src/microtar.c and locate the raw_to_header() function; search for strcpy() calls copying into 100-byte buffers for name or linkname fields
    Affected if The raw_to_header() function contains strcpy() copying into ustar header fields without bounds checking
  5. Check if application processes untrusted TAR archives
    Review data flow: does your application accept TAR files from users, APIs, or network sources and pass them to microtar functions
    Affected if Your application processes TAR archives from untrusted sources without prior validation

Your environment is affected if microtar version 0.1.0 or earlier is in use and your application processes untrusted TAR archives via mtar_open(), mtar_find(), or mtar_read_header() with the vulnerable strcpy() pattern present in source.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Replace strcpy() calls with bounds-safe alternatives (strncpy, snprintf, or memcpy with explicit null termination) and add validation to ensure fields are properly null-terminated before copying. Audit all other file parsing functions in microtar.c for similar issues.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,750
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-43623 in production — separate from our analysis above.

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What this is

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