CAPEC-476DetailedDraft
Signature Spoofing by Misrepresentation
An attacker exploits a weakness in the parsing or display code of the recipient software to generate a data blob containing a supposedly valid signature, but the signer's identity is falsely represented, which can lead to the attacker manipulating the recipient software or its victim user to perform compromising actions.
Open in catalog with CAPEC filter →Related vulnerabilities
CVE-2026-6213A vulnerability in Remote Spark SparkView before build 1122 allows an attacker to bypasses the local connection check and achieve arbitrary code execution as root on the server side. Depending on implementation the vulnerability can be exploited by an unauthenticated attacker.
CVE-2025-34063A cryptographic authentication bypass vulnerability exists in OneLogin AD Connector prior to 6.1.5 due to the exposure of a tenant’s SSO JWT signing key via the /api/adc/v4/configuration endpoint. An attacker in possession of the signing key can craft valid JWT tokens impersonating arbitrary users within a OneLogin tenant. The tokens allow authentication to the OneLogin SSO portal and all downstream applications federated via SAML or OIDC. This allows full unauthorized access across the victim’s SaaS environment.
CVE-2024-54085AMI’s SPx contains
a vulnerability in the BMC where an Attacker may bypass authentication remotely through the Redfish Host Interface. A successful exploitation
of this vulnerability may lead to a loss of confidentiality, integrity, and/or
availability.
CVE-2020-5415Concourse, versions prior to 6.3.1 and 6.4.1, in installations which use the GitLab auth connector, is vulnerable to identity spoofing by way of configuring a GitLab account with the same full name as another user who is granted access to a Concourse team. GitLab groups do not have this vulnerability, so GitLab users may be moved into groups which are then configured in the Concourse team.
CVE-2026-22797An issue was discovered in OpenStack keystonemiddleware 10.5 through 10.7 before 10.7.2, 10.8 and 10.9 before 10.9.1, and 10.10 through 10.12 before 10.12.1. The external_oauth2_token middleware fails to sanitize incoming authentication headers before processing OAuth 2.0 tokens. By sending forged identity headers such as X-Is-Admin-Project, X-Roles, or X-User-Id, an authenticated attacker may escalate privileges or impersonate other users. All deployments using the external_oauth2_token middleware are affected.
CVE-2024-6678An issue was discovered in GitLab CE/EE affecting all versions starting from 8.14 prior to 17.1.7, starting from 17.2 prior to 17.2.5, and starting from 17.3 prior to 17.3.2, which allows an attacker to trigger a pipeline as an arbitrary user under certain circumstances.
CVE-2026-48567Authentication bypass by spoofing in Azure HorizonDB allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-44649SillyTavern is a locally installed user interface that allows users to interact with text generation large language models, image generation engines, and text-to-speech voice models. Prior to 1.18.0, SillyTavern accepts Remote-User (Authelia) and X-Authentik-Username (Authentik) HTTP headers to automatically log in users when SSO is configured. There is no validation that these headers originate from a trusted reverse proxy. Any network client that can reach the SillyTavern port directly can inject these headers and authenticate as any user, including administrators, without a password. This vulnerability is exploitable only when sso.autheliaAuth: true or sso.authentikAuth: true is set in config.yaml (both default to false). This vulnerability is fixed in 1.18.0.
CVE-2026-44183Cleanuparr is a tool for automating the cleanup of unwanted or blocked files in Sonarr, Radarr, and supported download clients like qBittorrent. Prior to 2.9.10, TrustedNetworkAuthenticationHandler.ResolveClientIp parses the leftmost entry of the X-Forwarded-For header as the client IP. That entry is attacker-controlled — X-Forwarded-For is append-only, so the leftmost value is whatever the original HTTP client claimed. By sending a spoofed local IP in the header, an unauthenticated remote attacker passes the trusted-network check and is logged in as the Cleanuparr administrator. This vulnerability is fixed in 2.9.10.
CVE-2026-42354Sentry is an error tracking and performance monitoring tool. From version 21.12.0 to before version 26.4.1, a critical vulnerability was discovered in the SAML SSO implementation of Sentry. The vulnerability allows an attacker to take over any user account by using a malicious SAML Identity Provider and another organization on the same Sentry instance. The victim email address must be known in order to exploit this vulnerability. This issue has been patched in version 26.4.1.
CVE-2026-36537ThingsBoard v4.3.0.1 is vulnerable to an authentication bypass during the OAuth authorization code exchange. The application improperly trusts user-supplied identity data within the user parameter of the /login/oauth2/code/ endpoint. By manipulating the email address in this JSON object, a remote attacker can bypass authentication and gain full access to any existing user account on the platform without possessing the target user's credentials. This results in a complete account takeover.
CVE-2026-30975Sonarr is a PVR for Usenet and BitTorrent users. Versions prior to 4.0.16.2942 have an authentication bypass that affected users that had disabled authentication for local addresses (Authentication Required set to: `Disabled for Local Addresses`) without a reverse proxy running in front of Sonarr that didn't not pass through the invalid header. Patches are available in version 4.0.16.2942 in the nightly/develop branch and version 4.0.16.2944 for stable/main releases. Some workarounds are available. Make sure Sonarr's Authentication Required setting is set to `Enabled`, run Sonarr behind a reverse proxy, and/or do not expose Sonarr directly to the internet and instead rely on accessing it through a VPN, Tailscale or a similar solution.
CVE-2026-2800Spoofing issue in the WebAuthn component in Firefox for Android. This vulnerability was fixed in Firefox 148 and Thunderbird 148.
CVE-2026-24853Caido is a web security auditing toolkit. Prior to 0.55.0, Caido blocks non whitelisted domains to reach out through the 8080 port, and shows Host/IP is not allowed to connect to Caido on all endpoints. But this is bypassable by injecting a X-Forwarded-Host: 127.0.0.1:8080 header. This vulnerability is fixed in 0.55.0.
CVE-2025-66570cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.27.0, a vulnerability allows attacker-controlled HTTP headers to influence server-visible metadata, logging, and authorization decisions. An attacker can inject headers named REMOTE_ADDR, REMOTE_PORT, LOCAL_ADDR, LOCAL_PORT that are parsed into the request header multimap via read_headers() in httplib.h (headers.emplace), then the server later appends its own internal metadata using the same header names in Server::process_request without erasing duplicates. Because Request::get_header_value returns the first entry for a header key (id == 0) and the client-supplied headers are parsed before server-inserted headers, downstream code that uses these header names may inadvertently use attacker-controlled values. Affected files/locations: cpp-httplib/httplib.h (read_headers, Server::process_request, Request::get_header_value, get_header_value_u64) and cpp-httplib/docker/main.cc (get_client_ip, nginx_access_logger, nginx_error_logger). Attack surface: attacker-controlled HTTP headers in incoming requests flow into the Request.headers multimap and into logging code that reads forwarded headers, enabling IP spoofing, log poisoning, and authorization bypass via header shadowing. This vulnerability is fixed in 0.27.0.