CVE-2026-22036
Published: 14 January 2026
Summary
CVE-2026-22036 is a medium-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Nodejs Undici. Its CVSS base score is 5.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 5.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
This control implements explicit throttling on session allocation, addressing the weakness of allocating resources without limits.
Plan testing exercises resource allocation limits and throttling during simulated failures, directly addressing weaknesses that allow unbounded resource use.
Contingency plan updates ensure recovery strategies address unbounded resource allocation, making it harder for attackers to exploit lack of throttling to cause prolonged outages.
Provides continuity when unbounded resource allocation at the primary site leads to exhaustion and downtime.
Alternate services allow operations to continue when primary allocation of resources lacks limits or throttling.
Explicit planning of security-related actions requires defining limits, windows, and resource allocations, making allocation without throttling far less likely.
Measures of performance include tracking allocation behavior and throttling effectiveness, reducing the window for resource exhaustion attacks.
Imposes an inactivity-based limit on network resource allocation, throttling the number of concurrently held connections.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability enables client-side resource exhaustion DoS via malicious HTTP response with nested compression, directly matching application exploitation for endpoint denial of service.
NVD Description
Undici is an HTTP/1.1 client for Node.js. Prior to 7.18.0 and 6.23.0, the number of links in the decompression chain is unbounded and the default maxHeaderSize allows a malicious server to insert thousands compression steps leading to high CPU usage…
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and excessive memory allocation. This vulnerability is fixed in 7.18.0 and 6.23.0.
Deeper analysisAI
CVE-2026-22036 affects Undici, an HTTP/1.1 client library for Node.js, in versions prior to 7.18.0 and 6.23.0. The vulnerability stems from an unbounded number of links in the decompression chain combined with a default maxHeaderSize that permits a malicious server to insert thousands of compression steps. This results in high CPU usage and excessive memory allocation, classified under CWE-770 (Allocation of Resources Without Limits or Throttling) with a CVSS v3.1 base score of 5.9 (AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H).
A remote attacker with no privileges or user interaction required can exploit this over the network, though it demands high attack complexity. By controlling a server that a victim application connects to via Undici, the attacker crafts HTTP responses with deeply nested compression layers, triggering resource exhaustion on the client side and causing denial-of-service through CPU and memory overload.
The Undici security advisory (GHSA-g9mf-h72j-4rw9) and associated commit (b04e3cbb569c1596f86c108e9b52c79d8475dcb3) confirm the issue is resolved in versions 7.18.0 and 6.23.0, recommending immediate upgrades for affected Node.js applications using Undici.
Details
- CWE(s)