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CVE-2023-28756

MEDIUM · 5.3 CVSS v3.1 Published 2023-03-31
Fix available
A fix is available. Upgrade to after 2.7.7 or later.
See remediation →
62/100
Remediation priority · Elevated
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
A ReDoS issue was discovered in the Time component through 0.2.1 in Ruby through 3.2.1. The Time parser mishandles invalid URLs that have specific characters. It causes an increase in execution time for parsing strings to Time objects. The fixed versions are 0.1.1 and 0.2.2.

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 Regular Expression Denial of Service (ReDoS) vulnerability exists in Ruby's Time component library versions through 0.2.1. The Time parser incorrectly handles certain invalid URL strings containing specific characters, causing excessive computational time during parsing operations. Attackers can exploit this to cause denial of service by supplying crafted input strings that trigger exponentially increasing parse times.

MitigationUpdate the Time component gem to version 0.1.1 or 0.2.2 or later to obtain the security fix. Additionally, implement request rate limiting and input validation to mitigate ReDoS attempts in production environments.

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

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
RubyApplication
Affected:<= 2.7.7
TimeApplication
Affected:= 0.1.0= 0.2.1
Debian LinuxOperating system
Affected:= 10.0
FedoraOperating system
Affected:= 36= 37= 38

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
Low

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

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. Check installed Ruby version
    Run 'ruby --version' to see the Ruby interpreter version
    Affected if Ruby version is 2.7.7 or lower (the bundled Time component in these versions is vulnerable)
  2. Check Time gem version
    Run 'gem list time' to list installed Time gem versions
    Affected if Time gem version is exactly 0.1.0 or exactly 0.2.1 (these versions contain the vulnerable parser)
  3. Identify Time gem usage in application
    Search project files (Gemfile, Gemfile.lock) for 'gem "time"' or require statements containing 'time' component
    Affected if The Time gem is explicitly required or listed as a dependency in the project
  4. Verify URL/time string parsing
    Search codebase for uses of Time.parse, Time.httpdate, or similar Time parsing methods that process external input
    Affected if Application parses time values from URL parameters or external strings (the vulnerable code path)
  5. Check Debian/Fedora package versions (if applicable)
    For Debian: 'dpkg -l | grep ruby'. For Fedora: 'rpm -qa | grep ruby'. Check the installed package version numbers
    Affected if Running Debian 10.0 or Fedora 36/37/38 with the vulnerable Ruby/Time packages installed

You are affected if your Ruby version is 2.7.7 or lower, OR your Time gem version is 0.1.0 or 0.2.1, AND your application parses time values from external URL strings using the Time component.

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.

dbcve · scoped
Upgrade available Upgrade to a release after 2.7.7
Interim mitigation

Update the Time component gem to version 0.1.1 or 0.2.2 or later to obtain the security fix. Additionally, implement request rate limiting and input validation to mitigate ReDoS attempts in production environments.

Recommended fix High confidence

Time gem 0.1.1 or 0.2.2 (or Ruby >= 3.2.2)

  1. Identify the Time gem version in your project by running `gem list time` or checking your Gemfile
  2. If using Time gem 0.1.x: Run `gem install time -v 0.1.1` to upgrade to the fixed version
  3. If using Time gem 0.2.x: Run `gem install time -v 0.2.2` to upgrade to the fixed version
  4. Update your Gemfile to specify the fixed version: `gem 'time', '~> 0.1.1'` or `gem 'time', '~> 0.2.2'`
  5. Run `bundle update time` to update the gem in your project
  6. Alternatively, upgrade Ruby to a version >= 3.2.2 which includes the fixed Time component
Caveat Minimal risk; the fix addresses a ReDoS vulnerability with no reported breaking changes in the patch releases

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Ruby Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,340
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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-2023-28756 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data