Summary
OpenTelemetry JavaScript: Denial of service in JaegerPropagator via unhandled exception on a malformed header
@opentelemetry/propagator-jaeger decodes incoming HTTP header values with decodeURIComponent() without handling decode errors. A single request carrying a malformed percent-encoded value (for example a bare %) in an uber-trace-id or uberctx-* header throws an uncaught URIError, terminating any Node.js process that uses JaegerPropagator as its active propagator.
Am I affected?
This issue affects only a specific, opt-in configuration. If you use OpenTelemetry's default propagators (W3C TraceContext and Baggage), you are not affected.
You are affected only if you have registered JaegerPropagator as the active propagator. Check for:
@opentelemetry/propagator-jaegerin your dependency tree, andOTEL_PROPAGATORSset tojaeger(Jaeger only), or a directpropagation.setGlobalPropagator(new JaegerPropagator())call in your code.
Note: if JaegerPropagator is combined with other propagators through a CompositePropagator (for example OTEL_PROPAGATORS=jaeger,tracecontext), the process does not terminate - the composite propagator catches the error - but affected requests silently fail to extract context. You should still upgrade.
Patched versions
@opentelemetry/propagator-jaeger2.9.0
Details
JaegerPropagator.extract() calls decodeURIComponent() on raw header values at two unguarded call sites: the uber-trace-id trace header and each uberctx-* baggage value. decodeURIComponent() throws URIError: URI malformed on invalid percent-encoding. Because the HTTP instrumentation extracts context before its request-handler error wrapper, and a single configured propagator is not wrapped in a CompositePropagator (which would otherwise catch the error), the exception propagates as an uncaughtException and terminates the process.
Proof of concept
Against a service using JaegerPropagator:
curl -H 'uberctx-user: %' http://target/
# or
curl -H 'uber-trace-id: %' http://target/
The Node.js process exits with URIError: URI malformed and subsequent requests are refused.
Impact
Denial of Service: Any unauthenticated remote attacker who can send an HTTP request to a service that has JaegerPropagator registered as the global propagator (e.g. via OTEL_PROPAGATORS=jaeger or propagation.setGlobalPropagator(new JaegerPropagator())) can terminate the process with a single request. Confidentiality and integrity are not affected.
CVE-2026-59892 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.9.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
Update @opentelemetry/propagator-jaeger to 2.9.0 or later. The propagator now ignores header values it cannot decode instead of throwing.
Interim mitigation (if you cannot update): Trace-context headers should never be accepted unfiltered from untrusted callers. Until you can upgrade, strip or validate the uber-trace-id and uberctx-* headers on inbound requests at your edge - for example with a reverse proxy, API gateway, or load balancer (nginx, Envoy, etc.) - so that only trusted upstream services can set them.
Frequently Asked Questions
- What is CVE-2026-59892? CVE-2026-59892 is a high-severity security vulnerability in @opentelemetry/propagator-jaeger (npm), affecting versions < 2.9.0. It is fixed in 2.9.0.
- How severe is CVE-2026-59892? CVE-2026-59892 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of @opentelemetry/propagator-jaeger are affected by CVE-2026-59892? @opentelemetry/propagator-jaeger (npm) versions < 2.9.0 is affected.
- Is there a fix for CVE-2026-59892? Yes. CVE-2026-59892 is fixed in 2.9.0. Upgrade to this version or later.
- Is CVE-2026-59892 exploitable, and should I be worried? Whether CVE-2026-59892 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-59892 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-59892? Upgrade
@opentelemetry/propagator-jaegerto 2.9.0 or later.