CVE-2026-34829: Ruby rack · Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Multipart::Parser only wraps the
Affects ruby-rackSource GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 2.1.4-5ubuntu1.2+esm3 : patch ruby-rack soon.
Data as of 3 Nov 2026, 23:20 UTC
- Patch
- Available – fixed in 2.1.4-5ubuntu1.2+esm3, 2.2.7-1ubuntu0.7, 3.1.16-0.1ubuntu0.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 2 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.
What to do
Upgrade the Ubuntu ruby-rack to 2.1.4-5ubuntu1.2+esm3 (package) or 2.2.7-1ubuntu0.7 (package) or 3.1.16-0.1ubuntu0.3 (package).
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSruby-rackpkg:deb/ubuntu/ruby-rack?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10ruby-rackpkg:deb/ubuntu/ruby-rack?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSruby-rackpkg:deb/ubuntu/ruby-rack?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu Pro 22.04 LTSruby-rackpkg:deb/ubuntu/ruby-rack?arch=source&distro=esm-apps/jammyOther threats | Affected
| Fixed in
|
Ubuntu Pro 18.04 LTSruby-rackpkg:deb/ubuntu/ruby-rack?arch=source&distro=esm-apps/bionicOther threats | Affected
| Fixed in– |
Ubuntu Pro 16.04 LTSruby-rackpkg:deb/ubuntu/ruby-rack?arch=source&distro=esm-apps/xenialOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Apply the official patches by upgrading Ruby Rack to versions 2.2.23, 3.1.21, or 3.2.6 or later as provided by your distribution's security updates. For Ubuntu users, update to the package versions listed in USN-8182-1 and restart any Rack applications to apply the fix. No additional mitigation is required once patched.
Description
A vulnerability in Ruby Rack prior to versions 2.2.23, 3.1.21, and 3.2.6 allows an unauthenticated attacker to cause a denial of service by sending a multipart/form-data request without a Content-Length header. This leads to unbounded disk space consumption due to the multipart parser writing uploaded files directly to disk without size limits. The issue has been patched in the stated versions.