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Integer OverflowWeakness · CWE-190

CVE-2026-54417

HIGH · 7.5 CVSS v3.1 Published 2026-06-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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
An integer overflow in the mtar_next function in src/microtar.c in rxi microtar 0.1.0 allows a remote attacker to cause a denial of service (uncontrolled CPU consumption / infinite loop) via a crafted tar archive. mtar_next computes the offset to the next record as round_up(h.size, 512) + sizeof(mtar_raw_header_t) using 32-bit arithmetic.

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

Integer overflow in microtar 0.1.0's mtar_next() function allows a crafted tar archive to cause infinite loop/DoS. The function calculates record offset using 32-bit arithmetic as round_up(h.size, 512) + sizeof(mtar_raw_header_t). When the header size field is 0xFFFFFE00-0xFFFFFC01, the addition wraps to 0, causing mtar_next() to seek to its current position instead of advancing, resulting in 100% CPU consumption with no recovery.

MitigationUpgrade to a patched version of microtar that implements proper bounds checking and 64-bit arithmetic for offset calculations, or add validation to reject tar archives where the size field would cause integer overflow.

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
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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. Identify microtar library version
    Search for microtar in your codebase or dependencies (check package.json, Cargo.toml, requirements.txt, go.mod, or similar dependency files). Look for microtar or mtar references and note the version number.
    Affected if Version is 0.1.0 (the only affected version per the CVE summary)
  2. Locate the microtar source code
    Find the microtar source files in your project (typically named microtar.c, microtar.h, or mtar.c). Open the source and look for the mtar_next function definition.
    Affected if The source file shows version 0.1.0 in comments/headers, or matches the vulnerable code pattern using 32-bit arithmetic for offset calculation.
  3. Verify 32-bit arithmetic is used
    In the mtar_next function source, look for the record offset calculation pattern: round_up(h.size, 512) + sizeof(mtar_raw_header_t). Check if it uses 32-bit types (int, unsigned int, long) without 64-bit overflow protection.
    Affected if The calculation uses 32-bit types and lacks bounds checking before the addition, making integer overflow possible.
  4. Identify tar processing code paths
    Search your codebase for calls to mtar_next(), mtar_open(), or mtar_read(). Determine if your application processes tar archives from untrusted sources (user uploads, network data, external files).
    Affected if Your code calls mtar_next() to iterate through tar archives, especially those from untrusted or user-supplied sources.
  5. Check archive source trust
    Review where tar archives are loaded in your application. Determine if they originate from trusted internal sources or from untrusted external inputs (file uploads, API payloads, network downloads).
    Affected if Tar archives processed by microtar come from untrusted sources where an attacker could control the header size field.

You are affected if you use microtar version 0.1.0 and process tar archives from untrusted sources where an attacker can control the header size field to values between 0xFFFFFE00 and 0xFFFFFC01.

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

Upgrade to a patched version of microtar that implements proper bounds checking and 64-bit arithmetic for offset calculations, or add validation to reject tar archives where the size field would cause integer overflow.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2026-54417 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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