Raw vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-33508 is a high-severity Uncontrolled Recursion (CWE-674) vulnerability in Parseplatform Parse-Server. Its CVSS base score is 8.2 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 27th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SC-5 (Denial-of-service Protection) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-33508 affects Parse Server, an open source backend deployable on any Node.js-compatible infrastructure. The vulnerability resides in the LiveQuery component, which fails to enforce the requestComplexity.queryDepth configuration setting during WebSocket subscription request processing in versions prior to 8.6.56 and 9.6.0-alpha.45. This flaw, classified under CWE-674 (Uncontrolled Recursion), enables an attacker to submit a subscription request containing deeply nested logical operators, triggering excessive recursion and high CPU consumption that leads to service degradation or denial of service. The issue carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), indicating high severity due to its availability impact.
Any unauthenticated remote attacker can exploit this vulnerability over the network with low complexity and no user interaction required. By crafting and sending a malicious WebSocket subscription request with nested operators exceeding the intended query depth limits, the attacker induces unbounded recursion in the LiveQuery processing logic, resulting in resource exhaustion and potential disruption of Parse Server's availability for legitimate users.
Parse Server maintainers have addressed the issue in versions 8.6.56 and 9.6.0-alpha.45, where the LiveQuery component now properly enforces the requestComplexity.queryDepth setting. Security practitioners should upgrade to these patched versions immediately. Detailed patch information is available in GitHub commits 060d27053fb0fadf613c25aabab7fe0c82b7a899 and 2126fe4e12f9b399dc6b4b6a3fa70cb1825f159b, pull requests #10259 and #10260, and the security advisory at GHSA-6qh5-m6g3-xhq6.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-20071
Vulnerability Data
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.56 and 9.6.0-alpha.45, Parse Server's LiveQuery component does not enforce the requestComplexity.queryDepth configuration setting when processing WebSocket subscription requests.…
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An attacker can send a subscription with deeply nested logical operators, causing excessive recursion and CPU consumption that degrades or disrupts service availability. This issue has been patched in versions 8.6.56 and 9.6.0-alpha.45.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Input validation can reject or constrain data that would otherwise drive unbounded recursive calls.
DoS protection mechanisms limit the resource-exhaustion impact of uncontrolled recursion without eliminating the flaw.
System monitoring can observe anomalous resource consumption that signals runaway recursion after it begins.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly prevent coding errors such as missing recursion limits or termination conditions.
Runtime monitoring of compute resources can detect excessive consumption caused by uncontrolled recursion.
Vulnerability identification processes can discover and record uncontrolled recursion flaws before deployment.
Capacity monitoring and resource provisioning can absorb or limit the impact of runaway recursion.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development can detect excessive recursion via static analysis or fuzzing.
Secure development life cycle requires controls that prevent uncontrolled recursion through design and code review.
Application security requirements can mandate recursion limits or stack-depth checks.
Secure system architecture principles include resource-management and input-validation rules that limit recursion.
Secure coding standards directly prohibit or constrain recursive constructs that could exhaust stack or memory.
Capacity management includes monitoring and limits that mitigate resource exhaustion from runaway recursion.