Vulnerability in Open-Telemetry Opentelemetry-Java

CVE-2026-118259

opentelemetry-java is the Java implementation of the OpenTelemetry API for recording telemetry, and SDK for managing telemetry recorded by the API. Prior to 1.67.0, W3CTraceContextPropagator.extract() uses regex delimiter processing that can exhibit quadratic backtracking while parsing tracestate headers containing long runs of spaces or tabs without a following comma. An unauthenticated attacker whose headers reach extraction can repeatedly block request or event-loop threads and cause excessive CPU consumption, with practical impact bounded by ingress header-size limits, proxy configuration, and threading. This issue is fixed in version 1.67.0.

Vulnerability class: ReDoS (Regular Expression Denial of Service)

Published .

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-118259?
CVE-2026-118259 is a medium-severity vulnerability in Open-Telemetry Opentelemetry-Java, classified under Inefficient Regular Expression Complexity. CVSS score: 5.3/10. Published 2026-10-28.
How severe is CVE-2026-118259?
Medium severity. CVSS v3 base score is 5.3 out of 10.