CVE-2026-34829 | Rack up to 2.2.22/3.1.20/3.2.5 Rack::Multipart CONTENT_LENGTH resource consumption (GHSA-8vqr-qjwx-82mw)

VDB-354945 · CVE-2026-34829 · GHSA-8VQR-QJWX-82MW RACK UP TO 2.2.22/3.1.20/3.2.5 RACK::MULTIPART CONTENT_LENGTH RESOURCE CONSUMPTION HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 6.3 $0-$5k 0.85+ Summaryinfo A vulnerability has been found in Rack up to 2.2.22/3.1.20/3.2.5 and classified as problematic. This affects the function Rack::Multipart. Performing a manipulation of the argument CONTENT_LENGTH results in resource consumption. This vulnerability is known as CVE-2026-34829. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded. Detailsinfo A vulnerability, which was classified as problematic, was found in Rack up to 2.2.22/3.1.20/3.2.5. This affects the function Rack::Multipart. The manipulation of the argument CONTENT_LENGTH with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on availability. The summary by CVE is: Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Multipart::Parser only wraps the request body in a BoundedIO when CONTENT_LENGTH is present. When a multipart/form-data request is sent without a Content-Length header, such as with HTTP chunked transfer encoding, multipart parsing continues until end-of-stream with no total size limit. For file parts, the uploaded body is written directly to a temporary file on disk rather than being constrained by the buffered in-memory upload limit. An unauthenticated attacker can therefore stream an arbitrarily large multipart file upload and consume unbounded disk space. This results in a denial of service condition for Rack applications that accept multipart form data. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6. The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-34829 since 03/30/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue. Upgrading to version 2.2.23, 3.1.21 or 3.2.6 eliminates this vulnerability. Productinfo Name Rack Version 2.2.0 2.2.1 2.2.2 2.2.3 2.2.4 2.2.5 2.2.6 2.2.7 2.2.8 2.2.9 2.2.10 2.2.11 2.2.12 2.2.13 2.2.14 2.2.15 2.2.16 2.2.17 2.2.18 2.2.19 2.2.20 2.2.21 2.2.22 3.1.0 3.1.1 3.1.2 3.1.3 3.1.4 3.1.5 3.1.6 3.1.7 3.1.8 3.1.9 3.1.10 3.1.11 3.1.12 3.1.13 3.1.14 3.1.15 3.1.16 3.1.17 3.1.18 3.1.19 3.1.20 3.2.0 3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 Website Product: https://github.com/rack/rack/ CPE 2.3info 🔒 🔒 🔒 CPE 2.2info 🔒 🔒 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv3info VulDB Meta Base Score: 6.4 VulDB Meta Temp Score: 6.3 VulDB Base Score: 5.3 VulDB Temp Score: 5.1 VulDB Vector: 🔒 VulDB Reliability: 🔍 CNA Base Score: 7.5 CNA Vector (GitHub_M): 🔒 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Resource consumption CWE: CWE-400 / CWE-404 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Yes Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: Rack 2.2.23/3.1.21/3.2.6 Timelineinfo 03/30/2026 CVE reserved 04/02/2026 +3 days Advisory disclosed 04/02/2026 +0 days VulDB entry created 04/02/2026 +0 days VulDB entry last update Sourcesinfo Product: github.com Advisory: GHSA-8vqr-qjwx-82mw Status: Confirmed CVE: CVE-2026-34829 (🔒) GCVE (CVE): GCVE-0-2026-34829 GCVE (VulDB): GCVE-100-354945 Entryinfo Created: 04/02/2026 19:33 Changes: 04/02/2026 19:33 (65) Complete: 🔍 Cache ID: 99:3C7:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸