Rubygems.org is the Ruby community's gem hosting service. Rubygems.org users with MFA enabled would normally be protected from account takeover in the case of email account takeover. However, a workaround on the forgotten password form allows an attacker to bypass the MFA requirement and takeover the account. This vulnerability has been patched in commit 0b3272a.

Rubygems.org is the Ruby community's gem hosting service. A Gem publisher can cause a Remote DoS when publishing a Gem. This is due to how Ruby reads the Manifest of Gem files when using Gem::Specification.fromyaml. fromyaml makes use of SafeYAML.load which allows YAML aliases inside the YAML-based metadata of a gem. YAML aliases allow for Denial of Service attacks with so-called YAML-bombs (comparable to Billion laughs attacks). This was patched. There is is no action required by users. This issue is also tracked as GHSL-2024-001 and was discovered by the GitHub security lab.

Rubygems is a package registry used to supply software for the Ruby language ecosystem. Due to a bug in the yank action, it was possible for any RubyGems.org user to remove and replace certain gems even if that user was not authorized to do so. To be vulnerable, a gem needed: one or more dashes in its name creation within 30 days OR no updates for over 100 days At present, we believe this vulnerability has not been exploited. RubyGems.org sends an email to all gem owners when a gem version is published or yanked. We have not received any support emails from gem owners indicating that their gem has been yanked without authorization. An audit of gem changes for the last 18 months did not find any examples of this vulnerability being used in a malicious way. A deeper audit for any possible use of this exploit is ongoing, and we will update this advisory once it is complete. Using Bundler in --frozen or --deployment mode in CI and during deploys, as the Bundler team has always recommended, will guarantee that your application does not silently switch to versions created using this exploit. To audit your application history for possible past exploits, review your Gemfile.lock and look for gems whose platform changed when the version number did not change. For example, gemname-3.1.2 updating to gemname-3.1.2-java could indicate a possible abuse of this vulnerability. RubyGems.org has been patched and is no longer vulnerable to this issue as of the 5th of May 2022.

RubyGems.org is the Ruby community gem host. A bug in password & email change confirmation code allowed an attacker to change their RubyGems.org account's email to an unowned email address. Having access to an account whose email has been changed could enable an attacker to save API keys for that account, and when a legitimate user attempts to create an account with their email (and has to reset password to gain access) and is granted access to other gems, the attacker would then be able to publish and yank versions of those gems. Commit number 90c9e6aac2d91518b479c51d48275c57de492d4d contains a patch for this issue.

RubyGems is a package registry used to supply software for the Ruby language ecosystem. An ordering mistake in the code that accepts gem uploads allowed some gems (with platforms ending in numbers, like arm64-darwin-21) to be temporarily replaced in the CDN cache by a malicious package. The bug has been patched, and is believed to have never been exploited, based on an extensive review of logs and existing gems by rubygems. The easiest way to ensure that an application has not been exploited by this vulnerability is to verify all downloaded .gems checksums match the checksum recorded in the RubyGems.org database. RubyGems.org has been patched and is no longer vulnerable to this issue.

Last updated 24 July 2024

Last updated 18 August 2025

Last updated 11 July 2025

Last updated 11 July 2025

Summary A publisher on a publify application is able to perform a cross-site scripting attack on an administrator using the redirect functionality.

Details A publisher on a publify application is able to perform a cross-site scripting attack on an administrator using the redirect functionality. The exploitation of this XSS vulnerability requires the administrator to click a malicious link.

We can create a redirect to a javascript:alert() URL. Whilst the redirect itself doesn't work, on the administrative panel, an a tag is created with the payload as the URI. Upon clicking this link, the XSS is triggered.

An attack could attempt to hide their payload by using HTML, or other encodings, as to not make it obvious to an administrator that this is a malicious link.

PoC A publisher can create a new redirect as shown below. The payload used is javascript:alert(). !image

An administrator will now see this redirect in their overview of the page. !image

If they click the link on the right, it triggers the XSS. !image

Impact A publisher may attempt to use this vulnerability to escalate their privileges and become an administrator.

Last updated 18 August 2025

Improper verification of signatures in tarball allows to install mis-signed gem when tarball contain multiple gem signatures.

Upstream fix:

https://github.com/rubygems/rubygems/commit/f5042b879259b1f1ce95a0c5082622c646376693

External References:

https://www.ruby-lang.org/en/news/2018/02/17/multiple-vulnerabilities-in-rubygems/

Last updated 18 August 2025

Cross-site scripting vulnerability in homepage attribute when displayed via gem server was found.

Upstream fix:

https://github.com/rubygems/rubygems/commit/66a28b9275551384fdab45f3591a82d6b59952cb

External References:

https://www.ruby-lang.org/en/news/2018/02/17/multiple-vulnerabilities-in-rubygems/

Last updated 18 August 2025

Last updated 18 August 2025

Last updated 18 August 2025

Last updated 24 July 2024

rubygems.org is the Ruby community's primary gem (library) hosting service. Insufficient input validation allowed malicious actors to replace any uploaded gem version that had a platform, version number, or gem name matching /-\d/, permanently replacing the legitimate upload in the canonical gem storage bucket, and triggering an immediate CDN purge so that the malicious gem would be served immediately. The maintainers have checked all gems matching the /-\d/ pattern and can confirm that no unexpected .gems were found. As a result, we believe this vulnerability was not exploited. The easiest way to ensure that a user's applications were not exploited by this vulnerability is to check that all of your downloaded .gems have a checksum that matches the checksum recorded in the RubyGems.org database. RubyGems contributor Maciej Mensfeld wrote a tool to automatically check that all downloaded .gem files match the checksums recorded in the RubyGems.org database. You can use it by running: bundle add bundler-integrity followed by bundle exec bundler-integrity. Neither this tool nor anything else can prove you were not exploited, but the can assist your investigation by quickly comparing RubyGems API-provided checksums with the checksums of files on your disk. The issue has been patched with improved input validation and the changes are live. No action is required on the part of the user. Users are advised to validate their local gems.

fastreader Gem for Ruby contains a flaw that is triggered during the handling of specially crafted input passed via a URL that contains a ';' character. This may allow a context-dependent attacker to potentially execute arbitrary commands.

commandwrap.rb in the commandwrap Gem for Ruby allows remote attackers to execute arbitrary commands via shell metacharacters in a URL or filename.

A flaw was corrected in rubygem-mail version 2.4.4:

A file system traversal in filedelivery method [1].

[1] https://github.com/mikel/mail/commit/29aca25218e4c82991400eb9b0c933626aefc98f

The Mail gem before 2.4.3 for Ruby allows remote attackers to execute arbitrary commands via shell metacharacters in a (1) sendmail or (2) exim delivery.

RubyGems before 1.8.23 can redirect HTTPS connections to HTTP, which makes it easier for remote attackers to observe or modify a gem during installation via a man-in-the-middle attack.

RubyGems before 1.8.23 does not verify an SSL certificate, which allows remote attackers to modify a gem during installation via a man-in-the-middle attack.

Algorithmic complexity vulnerability in Gem::Version::ANCHOREDVERSIONPATTERN in lib/rubygems/version.rb in RubyGems before 1.8.23.2, 1.8.24 through 1.8.26, 2.0.x before 2.0.10, and 2.1.x before 2.1.5, as used in Ruby 1.9.0 through 2.0.0p247, allows remote attackers to cause a denial of service (CPU consumption) via a crafted gem version that triggers a large amount of backtracking in a regular expression. NOTE: this issue is due to an incomplete fix for CVE-2013-4287.

Algorithmic complexity vulnerability in Gem::Version::VERSIONPATTERN in lib/rubygems/version.rb in RubyGems before 1.8.23.1, 1.8.24 through 1.8.25, 2.0.x before 2.0.8, and 2.1.x before 2.1.0, as used in Ruby 1.9.0 through 2.0.0p247, allows remote attackers to cause a denial of service (CPU consumption) via a crafted gem version that triggers a large amount of backtracking in a regular expression.

lib/minimagick.rb in the MiniMagick Gem 1.3.1 for Ruby allows remote attackers to execute arbitrary commands via shell metacharacters in a URL.

Aaron Patterson of Ruby on Rails project reports:

Denial of Service and Unsafe Object Creation Vulnerability in JSON

There is a denial of service and unsafe object creation vulnerability in the json gem. This vulnerability has been assigned the CVE identifier CVE-2013-0269.

Versions Affected: All. This includes JSON that ships with Ruby 1.9.X-pXXX Not affected: NONE Fixed Versions: 1.7.7, 1.6.8, 1.5.5

Impact ------ When parsing certain JSON documents, the JSON gem can be coerced in to creating Ruby symbols in a target system. Since Ruby symbols are not garbage collected, this can result in a denial of service attack.

The same technique can be used to create objects in a target system that act like internal objects. These "act alike" objects can be used to bypass certain security mechanisms and can be used as a spring board for SQL injection attacks in Ruby on Rails.

Impacted code looks like this:

JSON.parse(userinput)

Where the userinput variable will have a JSON document like this:

{"jsonclass":"foo"}

The JSON gem will attempt to look up the constant "foo". Looking up this constant will create a symbol.

In JSON version 1.7.x, objects with arbitrary attributes can be created using JSON documents like this:

{"jsonclass":"JSON::GenericObject","foo":"bar"}

This document will result in an instance of JSON::GenericObject, with the attribute "foo" that has the value "bar". Instantiating these objects will result in arbitrary symbol creation and in some cases can be used to bypass security measures.

PLEASE NOTE: this behavior does not change when using JSON.load. JSON.load should never be given input from unknown sources. If you are processing JSON from an unknown source, always use JSON.parse.

All users running an affected release should either upgrade or use one of the work arounds immediately.

Releases -------- The FIXED releases are available at the normal locations.

Workarounds ----------- For users that cannot upgrade, please use the attached patches. If you cannot use the attached patches, change your code from this:

JSON.parse(json)

To this:

JSON.parse(json, :createadditions => false)

If you cannot change the usage of JSON.parse (for example you're using a gem which depends on JSON.parse like multijson), then apply this monkey patch:

module JSON class << self alias :oldparse :parse def parse(json, args = {}) args[:createadditions] = false oldparse(json, args) end end end

Patches ------- To aid users who aren't able to upgrade immediately we have provided patches for the three supported release series. They are in git-am format and consist of a single changeset.

1-7-VULN.patch - Patch for the 1.7 series 1-6-VULN.patch - Patch for the 1.6 series 1-5-VULN.patch - Patch for the 1.5 series

Credits ------- Thomas Hollstegge of Zweitag (www.zweitag.de) Ben Murphy