RubyGems vulnerable to Deserialization of Untrusted DataGHSA-mqwr-4qf2-2hcv
CRITICALFix: rubygems/rubygems@510b163GHSA-mqwr-4qf2-2hcv is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in rubygems-update. EPSS puts its 30-day exploitation probability at 15.9% (97th percentile). A fix is available for rubygems-update — see the affected versions and patch details below.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
rubygems-updateReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
RubyGems versions between 2.0.0 and 2.6.13 are vulnerable to a possible remote code execution vulnerability. YAML deserialization of gem specifications can bypass class white lists. Specially crafted serialized objects can possibly be used to escalate to remote code execution. The issue has been patched in 2.6.14.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | rubygems-update | ≥ 2.0.0&&< 2.6.14 | 2.6.14bundle update rubygems-update --conservative |
Affected Products
ubuntu linuxcanonicaldebian linuxdebianenterprise linux desktopredhatenterprise linux serverredhatenterprise linux server ausredhatenterprise linux server eusredhatDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rubygems-update, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update rubygems-update to 2.6.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mqwr-4qf2-2hcv is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This issue did not affect the versions of rubygems as shipped with Red Hat Enterprise Linux 6. This issue affects the versions of ruby as shipped with Red Hat Enterprise Linux 7 and the versions of rh-ruby22-ruby and rh-ruby23-ruby as shipped with Red Hat Software Collections. Red Hat Product Security has rated this…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 7 | ruby-0:2.0.0.648-33.el7_4 | RHSA-2018:0378 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | rh-ruby24-ruby-0:2.4.2-86.el6 | RHSA-2017:3485 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | rh-ruby22-ruby-0:2.2.9-19.el6 | RHSA-2018:0583 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | rh-ruby23-ruby-0:2.3.6-67.el6 | RHSA-2018:0585 |
Frequently Asked Questions
Is GHSA-mqwr-4qf2-2hcv in your dependencies?
Find it across RubyGems, including transitive dependencies.