EUVD-2026-54430
GHSA-jrwc-g36x-gqc7
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/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:X
Network-reachable, no privileges required, user interaction needed to click crafted link; scope changes to external system (victim browser/session), with low confidentiality and integrity impact from phishing and header injection.
Primary rating from Vendor (NCSC.ch).
CVSS VectorVendor: NCSC.ch
Lifecycle Timeline
1DescriptionCVE.org
The Webbox of TeamDavid by Tobit Laboratories AG constructs redirect URLs using user-supplied input, which is appended to the redirect target in a 302 HTTP response. By using URL-encoded characters such as “%2e” (representing a dot), an attacker can manipulate the portion of the URL following the top-level domain (TLD). If a similar, registerable TLD exists (for example, if “.com” is the application’s domain, and “.company” is available for registration), an attacker can craft a URL to redirect users to a malicious “.company” domain. By using URL-encoded line feeds, it becomes possible to insert arbitrary response headers in the server's HTTP response.
This issue affects TeamDavid through Rollout 524.
AnalysisAI
Open redirect and HTTP response header injection in the Webbox component of TeamDavid (by Tobit Laboratories AG) allow unauthenticated network attackers to manipulate 302 redirect responses by supplying encoded characters in user-controlled URL parameters. Using URL-encoded dots (%2e), an attacker can steer victims toward attacker-registered lookalike TLD domains (e.g., redirecting from a .com application to an attacker-owned .company domain), while URL-encoded line feeds enable HTTP response splitting to inject arbitrary headers. No public exploit or CISA KEV listing has been identified at time of analysis; this CVE is one of 22 disclosed against the David product suite by infoguard.ch researchers.
Technical ContextAI
TeamDavid, marketed by Tobit Laboratories AG as a Microsoft 365 alternative, exposes a web interface component called Webbox that constructs Location header values in 302 HTTP redirect responses by concatenating user-supplied input without adequate sanitization. CWE-601 (URL Redirection to Untrusted Site - Open Redirect) identifies the root cause as insufficient validation of redirect destinations. The compounding issue is HTTP response splitting: because URL-encoded line feed characters (%0a/%0d) are not stripped before inclusion in the Location header, an attacker can terminate the Location value mid-line and inject additional arbitrary HTTP response headers. The CPE cpe:2.3:a:tobit_laboratories_ag:teamdavid:*:*:*:*:*:*:*:* covers all TeamDavid versions up to and including Rollout 524. The TLD-manipulation variant specifically exploits the fact that many TLD namespace collisions are plausible (e.g., .com vs .company, .net vs .network), allowing redirect destinations to appear legitimate in truncated URL displays.
RemediationAI
Upgrade TeamDavid beyond Rollout 524 by consulting vendor release notes at https://david.tobit.software/releasenotes to identify the specific remediated rollout version; the exact patched version is not confirmed in the available data and must be verified with Tobit Laboratories AG. If immediate patching is not feasible, implement server-side redirect destination whitelisting to permit only known-safe redirect targets - this eliminates both the open redirect and the header injection vector by preventing arbitrary user input from reaching the Location header. As an additional layer, deploy a WAF rule to block requests containing URL-encoded newline sequences (%0a, %0d, %0A, %0D) in redirect parameters; note this may block edge-case legitimate encoded input. Blocking URL-encoded dot sequences (%2e) in redirect parameters is a narrower compensating control but carries a higher risk of false positives. User-awareness of lookalike domain phishing is a non-technical mitigation of last resort.
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