Is CVE-2026-118259 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-118259 being exploited in the wild.

How severe is CVE-2026-118259?

Medium severity, with a CVSS score of 5.3, published 28 October 2026.

Which products and versions are affected?

io.opentelemetry:opentelemetry-api (Maven) <= 1.66.0, ECOSYSTEM:introduced=0,fixed=1.67.0; Opentelemetry-Java before 1.67.0.

Is there a fix for CVE-2026-118259?

Yes. io.opentelemetry:opentelemetry-api (Maven): upgrade to 1.67.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-118259 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-118259?

Check whether you run io.opentelemetry:opentelemetry-api (Maven) or Opentelemetry-Java at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-118259: OpenTelemetry Java regex backtracking in W3CTraceContextPropagator

Q: Is there a fix for CVE-2026-118259?

Yes. io.opentelemetry:opentelemetry-api (Maven): upgrade to 1.67.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-118259 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-118259?

Check whether you run io.opentelemetry:opentelemetry-api (Maven) or Opentelemetry-Java at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-118259 · Severity: medium · CVSS 5.3 · Published 2026-10-28

OpenTelemetry Java is a library used by applications to record and export telemetry data (traces, metrics, logs). A flaw in the W3CTraceContextPropagator component allows an attacker to send specially crafted HTTP headers with long runs of whitespace that trigger excessive regex backtracking, causing severe CPU consumption and blocking request threads. This can lead to denial of service by exhausting server resources.

Vendors: Maven, Opentelemetry.

Quick answers

Is CVE-2026-118259 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-118259 being exploited in the wild.
How severe is CVE-2026-118259?: Medium severity, with a CVSS score of 5.3, published 28 October 2026.
Which products and versions are affected?: io.opentelemetry:opentelemetry-api (Maven) <= 1.66.0, ECOSYSTEM:introduced=0,fixed=1.67.0; Opentelemetry-Java before 1.67.0.
Is there a fix for CVE-2026-118259?: Yes. io.opentelemetry:opentelemetry-api (Maven): upgrade to 1.67.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-118259 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-118259?: Check whether you run io.opentelemetry:opentelemetry-api (Maven) or Opentelemetry-Java at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

io.opentelemetry:opentelemetry-api (Maven): upgrade to 1.67.0 or later

# set io.opentelemetry:opentelemetry-api to 1.67.0 in your pom.xml or build.gradle

Technical details

The W3CTraceContextPropagator.extract() method uses a regex pattern with quadratic backtracking behavior when parsing tracestate headers containing long runs of spaces or tabs without a following comma. An unauthenticated attacker can exploit this via network headers to block event-loop and request threads with practical impact bounded by ingress header-size limits. The vulnerability is fixed by removing regex-based parsing in favor of deterministic character-by-character parsing.

Affected products

OpenTelemetry opentelemetry-java before 1.67.0

Identifiers

CVE-2026-118259
GHSA-ccrj-gw8r-854m

Timeline

2026-10-28: disclosed
2026-10-06: patched

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.