swift-otel swift-w3c-trace-context up to 1.0.3 OpenTelemetry Protocol denial of service

Summaryinfo

A vulnerability, which was classified as problematic, has been found in swift-otel swift-w3c-trace-context up to 1.0.3. This impacts an unknown function of the component OpenTelemetry Protocol. The manipulation leads to denial of service. This vulnerability is uniquely identified as CVE-2026-23886. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in swift-otel swift-w3c-trace-context up to 1.0.3. This issue affects an unknown functionality of the component OpenTelemetry Protocol. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. The summary by CVE is:

Swift W3C TraceContext is a Swift implementation of the W3C Trace Context standard, and Swift OTel is an OpenTelemetry Protocol (OTLP) backend for Swift Log, Swift Metrics, and Swift Distributed Tracing. Prior to Swift W3C TraceContext version 1.0.0-beta.5 and Swift OTel version 1.0.4, a denial-of-service vulnerability due to improper input validation allows a remote attacker to crash the service via a malformed HTTP header. This allows crashing the process with data coming from the network when used with, for example, an HTTP server. Most common way of using Swift W3C Trace Context is through Swift OTel. Version 1.0.0-beta.5 of Swift W3C TraceContext and version 1.0.4 of Swift OTel contain a patch for this issue. As a workaround, disable either Swift OTel or the code that extracts the trace information from an incoming header (such as a `TracingMiddleware`).

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-23886 since 01/16/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 1.0.0-beta.5 or 1.0.4 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 5da9b143ba6046734de3fa51dafea28290174e4e is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-3282). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• swift-otel

Name

• swift-w3c-trace-context

Version

• 1.0.0
• 1.0.1
• 1.0.2
• 1.0.3

License

• open-source

Website

• Product: https://github.com/swift-otel/swift-w3c-trace-context/

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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