dbcve.org
Out-of-bounds ReadWeakness · CWE-125

CVE-2020-26312

HIGH · 8.1 CVSS v3.1 Published 2024-05-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
87/100
Remediation priority · High
Remotely reachable 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
Dotmesh is a git-like command-line interface for capturing, organizing and sharing application states. In versions 0.8.1 and prior, the unsafe handling of symbolic links in an unpacking routine may enable attackers to read and/or write to arbitrary locations outside the designated target folder. The routine `untarFile` attempts to guard against creating symbolic links that point outside the directory a tar archive is extracted to. However, a malicious tarball first linking `subdir/parent` to `..` (allowed, because `subdir/..` falls within the archive root) and then linking `subdir/parent/escapes` to `..` results in a symbolic link pointing to the tarball’s parent directory, contrary to the routine’s goals. This issue may lead to arbitrary file write (with same permissions as the program running the unpack operation) if the attacker can control the archive file. Additionally, if the attacker has read access to the unpacked files, they may be able to read arbitrary system files the parent process has permissions to read. As of time of publication, no patch for this issue is available.

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

A symlink-based path traversal vulnerability in Dotmesh's `untarFile` function allows attackers to escape the intended extraction directory. By crafting a malicious tar archive with chained symbolic links (e.g., `subdir/parent` → `..` then `subdir/parent/escapes` → `..`), attackers can create symlinks pointing outside the designated target folder, enabling arbitrary file read/write with the same privileges as the unpacking process.

MitigationAvoid extracting untrusted tar archives until an official patch is released; if extraction is necessary, isolate the operation in a restricted container or VM with minimal filesystem permissions and monitor for suspicious symlink activity.

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

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

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. Verify Dotmesh installation
    Check if the dotmesh CLI or server component is present on the system. Look for executables named 'dm' or 'dotmesh' in PATH, or check for /opt/dotmesh, /usr/local/dotmesh, or ~/dotmesh directories.
    Affected if Dotmesh is installed on the system.
  2. Determine installed Dotmesh version
    Run 'dm --version' for CLI or check the Docker image tag or Helm chart version if running as a container/service. Compare against any known affected version ranges if documented.
    Affected if The installed version falls within any documented vulnerable version range.
  3. Identify use of untarFile functionality
    Review application logs, recent API calls, or audit trails for operations that invoke file import or tar extraction features. Check if the Dotmesh API endpoint for importing tar archives is publicly accessible or used internally.
    Affected if The untarFile function is invoked to extract untrusted tar archives.
  4. Audit extraction directories for symlink anomalies
    Inspect the designated extraction target directories (typically under /var/dotmesh or the configured data directory). Run 'find <extraction_dir> -type l -ls' to list all symbolic links and verify they point only within the intended directory structure.
    Affected if Any symbolic links exist that point outside the designated extraction directory (e.g., using '..' paths).
  5. Check for unauthorized file modifications outside extraction boundaries
    Compare the list of files created in extraction directories against expected boundaries. Use 'find <extraction_dir> -mtime <recent> -ls' to identify recently modified files and verify their paths resolve within the target folder.
    Affected if Files exist outside the intended extraction directory or unexpected files appear in parent directories.

A defender is affected if Dotmesh is installed and its untarFile function has processed untrusted tar archives, particularly if symbolic links in extraction directories point outside the intended folder or unexpected files appear in parent directories.

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

Avoid extracting untrusted tar archives until an official patch is released; if extraction is necessary, isolate the operation in a restricted container or VM with minimal filesystem permissions and monitor for suspicious symlink activity.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2020-26312 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2020-26312 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data