Apache Thrift Ruby bindings: Resource exhaustion via unbounded JSON string size
Summary
The Ruby bindings of Apache Thrift (thrift gem) contain a flaw in the TJsonProtocol component, which does not limit the size of strings it processes. A remote attacker who can send crafted JSON-encoded data to a Ruby service using this protocol can exhaust resources and cause a denial of service. No confidentiality or integrity impact is documented, and the attack requires no authentication or user interaction. Exposure depends on whether an application that uses Thrift's Ruby JSON protocol accepts untrusted input.
Affected
- Apache Thrift (Ruby bindings, gem thrift) before 0.25.0
- Versions 0 up to but excluding 0.25.0 are affected; default configuration is unaffected per the CNA record
Fixed in
- Apache Thrift 0.25.0 (gem thrift 0.25.0)
- Distribution package fixed versions: Unknown.
Workaround
- No vendor workaround documented.
- Interim measures (own suggestion, not from a source): limit request body sizes at the reverse proxy and avoid passing untrusted input to the Ruby JSON protocol.
Exploitation
- Known exploited in the wild: No evidence found; CISA KEV status not confirmed.
- Public proof of concept: none found in the indexes checked; this does not prove none exists.
- CISA SSVC: exploitation none, automatable no, technical impact partial.
Our recommendation
- Search Ruby projects, Gemfile.lock files, vendored gems and container images for the thrift gem.
- Upgrade affected instances that accept untrusted input to thrift 0.25.0.
- Check Ubuntu, Debian and Azure Linux packages for fixed versions.
- Re-check the NVD status (Deferred) and CISA KEV for changes.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Apache lists thread 1 lists.apache.org
- Apache lists thread 2 lists.apache.org
- RubyGems thrift 0.24.0 rubygems.org
- OSV Ubuntu CVE-2026-94656 osv.dev
- Vulners CVE-2026-94656 vulners.com
- OSV Azure Linux AZL-105932 osv.dev
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 17:12.
Original description (NVD)
Allocation of resources without limits or throttling vulnerability in Apache Thrift ruby bindings. This issue affects Apache Thrift: before 0.25.0. Users are recommended to upgrade to version 0.25.0, which fixes the issue.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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