CVE-2026-17615
HIGHCVE-2026-17615 is a high-severity (CVSS 7.5) XML External Entity (XXE) vulnerability. O3 Security confirms whether CVE-2026-17615 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
A flaw was found in RESTEasy's SourceProvider. This vulnerability allows an unauthenticated attacker to perform an unauthenticated remote file read. By sending a specially crafted XML…
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-17615.
Description
A flaw was found in RESTEasy's SourceProvider. This vulnerability allows an unauthenticated attacker to perform an unauthenticated remote file read. By sending a specially crafted XML body with a DOCTYPE declaration referencing external entities to an endpoint that accepts application/xml and returns Source or StreamSource, the server can be tricked into resolving the entity and including sensitive file contents in the HTTP response. This is due to the SourceProvider.writeTo() method creating a SAXParser without disabling external entity resolution, leading to an XML External Entity (XXE) vulnerability.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-17615 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-17615 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-17615. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-17615 in your dependencies?
O3 detects CVE-2026-17615 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.