What is CWE-441?
The product receives a request, message, or directive from an upstream component, but the product does not sufficiently preserve the original source of the request before forwarding the request to an external actor that is outside of the product's control sphere. This causes the product to appear to be the source of the request, leading it to act as a proxy or other intermediary between the upstream component and the external actor.
If an attacker cannot directly contact a target, but the product has access to the target, then the attacker can send a request to the product and have it be forwarded to the target. The request would appear to be coming from the product's system, not the attacker's system. As a result, the attacker can bypass access controls (such as firewalls) or hide the source of malicious requests, since the requests would not be coming directly from the attacker. Since proxy functionality and message-forwarding often serve a legitimate purpose, this issue only becomes a vulnerability when: The product runs with different privileges or on a different system, or otherwise has different levels of access than the upstream component; The attacker is prevented from making the request directly to the target; and The attacker can create a request that the proxy does not explicitly intend to be forwarded on the behalf of the requester. Such a request might point to an unexpected hostname, port number, hardware IP, or service. Or, the request might be sent to an allowed service, but the request could contain disallowed directives, commands, or resources.
CWE-441 is a class-level weakness in MITRE’s Common Weakness Enumeration. Applicable platforms: Not Language-Specific; Not OS-Specific; Not Architecture-Specific; Not Technology-Specific.
Source: MITRE CWE (CWE-441 definition, reproduced verbatim). Counts and linkage below are Threadlinqs data.
Consequences
- Non-Repudiation, Access Control — Gain Privileges or Assume Identity, Hide Activities, Execute Unauthorized Code or Commands
Source: MITRE CWE, common consequences.
How CWE-441 is exploited in the wild
Threadlinqs maps 6 CVEs to CWE-441, published between 2026-07-23 and 2026-10-01. 1 is listed in CISA’s Known Exploited Vulnerabilities catalog, the authoritative record of exploitation in the wild. By CVSS v3 severity the set splits into 4 critical, 2 high. The highest EPSS score in the set is 0.4% (CVE-2026-69399), the modelled probability of exploitation in the next 30 days. 11 tracked threats reference CWE-441 directly or through a CVE it covers; the most recent is “Critical Capacitor WebView Navigation Guard Bypass Lets Malicious Links Access App Data and Native Features (CVE-2026-103922)” (2026-10-04). Affected products concentrate in @capacitor (1), Elastic (1), Microsoft (1), among 9 vendors in total.
Vulnerabilities (CVEs)
All 6 CVEs mapped to CWE-441, CISA KEV first, then by CVSS score.
- CVE-2026-83548 — CISA KEV · CVSS 10 critical · EPSS 0.2% · published 2026-09-01
- CVE-2026-69399 — CVSS 10 critical · EPSS 0.4% · published 2026-09-17
- CVE-2026-42933 — CVSS 10 critical · EPSS 0.2% · published 2026-07-23
- CVE-2026-103922 — CVSS 9.3 critical · EPSS 0.2% · published 2026-10-01
- CVE-2026-77348 — CVSS 8.2 high · EPSS 0.2% · published 2026-08-31
- CVE-2026-72668 — CVSS 7.3 high · EPSS 0.1% · published 2026-09-26
Affected vendors
Threat activity
11 tracked threats cite CWE-441:
- Critical Capacitor WebView Navigation Guard Bypass Lets Malicious Links Access App Data and Native Features (CVE-2026-103922)CRITICAL
- ConfigConfusion: Missing Authorization Check in GCP Config Connector Lets a Kubernetes Namespace User Seize Organization OwnerCRITICAL
- Eclypsium InfraTrust Report: Mass Active Exploitation of Network Management Systems (Cisco FMC/ISE CVE-2026-20079, CVE-2026-76460; SonicWall SMA 1000 CVE-2026-83548/83549; Linux Kernel CopyFail CVE-2026-31431)CRITICAL
- Microsoft September 2026 Cloud Disclosure: 18 Elevation-of-Privilege, Information-Disclosure, and Spoofing Flaws Across Azure and Copilot AI Products, Plus a Windows Secure Kernel EoP (CVE-2026-85921)CRITICAL
- SonicWall SMA1000 Chained Vulnerabilities (CVE-2026-83548, CVE-2026-83549) Exploited in the WildCRITICAL
- CSS Bomb: JavaScript-Free CSS Keylogging and Token-Theft Attacks Against Gmail, Outlook, Yahoo Mail, AOL Mail, Fastmail, and ProtonMailHIGH
- RovoBlast: One-Click rovoChatPrompt Parameter-to-Prompt Injection in Atlassian Rovo Exposes Confluence, Jira, SharePoint, and Bitbucket DataCRITICAL
- RovoBlast: One-Click Parameter-to-Prompt Injection in Atlassian Rovo AI Exposes Confluence, Jira, and SharePoint DataCRITICAL
- Researcher Demonstrates Full C2 Inside ChatGPT Secure Sandbox via Chained Attack Techniques at Black Hat USA 2026HIGH
- Unpatched Claude for Chrome Extension Flaws Enable Unauthorized Account Actions via Fake Clicks and Permission BypassCRITICAL
- LMDeploy SSRF in load_image() Vision-Language Module (CVE-2026-33626) — Actively Exploited Within 13 Hours of DisclosureHIGH
Mitigations
- Architecture and Design: Enforce the use of strong mutual authentication mechanism between the two parties.
- Architecture and Design: Whenever a product is an intermediary or proxy for transactions between two other components, the proxy core should not drop the identity of the initiator of the transaction. The immutability of the identity of the initiator must be maintained and should be forwarded all the way to the target.
Source: MITRE CWE, potential mitigations.
Detection methods (MITRE CWE)
- Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
Source: MITRE CWE, detection methods. Threadlinqs detection rules for the threats above are Blue tier and higher.