XSS in Valhalla
CVE-2026-49294
Valhalla is an open source routing engine and accompanying libraries for use with OpenStreetMap data. Versions 3.6.3 and prior are vulnerable to reflected cross-site scripting (XSS) due to improper neutralization of input in the JSONP callback parameter. When a request specifies a JSONP callback, the value is reflected directly into the HTTP response body with Content-Type: application/javascript, without any validation, output encoding, or allowlist filtering. An attacker can craft a URL containing arbitrary JavaScript in the callback parameter; if a victim is induced to load that URL via a <script src="..."> tag, the injected script executes in the context of the serving origin, potentially leading to session token theft, credential disclosure, or actions performed on behalf of the victim. This issue was not fixed at time of publication.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (15.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 15.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.003 · change: +0.001
Affected products
- Valhalla — versions <= 3.6.3
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-49294?
- CVE-2026-49294 is a medium-severity vulnerability in Valhalla, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-06-15.
- How severe is CVE-2026-49294?
- Medium severity. CVSS v3 base score is 6.1 out of 10.