OpenTelemetry Python: Denial of service through quadratic-time traceparent parsing in opentelemetry-api

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-126360
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-13 00:20:11 UTC
Updated2026-11-13 00:20:11 UTC
DescriptionOpenTelemetry Python provides the Python API and SDK for OpenTelemetry. Prior to 1.45.2, TraceContextTextMapPropagator.extract() in opentelemetry-api can perform quadratic-time regular-expression backtracking on a malformed traceparent value containing a trace-context prefix, a long whitespace sequence, and an embedded newline. Exploitation requires an attacker-controlled carrier that preserves embedded newlines and permits a sufficiently large value, because conforming HTTP header values cannot contain embedded newlines. JSON-based carriers, including applicable MCP request metadata integrations, can preserve the required newline depending on the SDK, instrumentation, and message-size limits. Parsing on an asynchronous server's event-loop thread can consume excessive CPU and delay unrelated requests, while the advisory does not establish disclosure, modification, or code execution. This issue is fixed in version 1.45.2.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Problem Types: CWE-1333 | CWE-1333 CWE-1333: Inefficient Regular Expression Complexity

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
3.1CNADECLARED5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Open-telemetry Opentelemetry-python affected < 1.45.2 Not specified

References

ReferenceSourceLinkTags
github.com/open-telemetry/opentelemetry-python/security/advisories/GHSA-... [email protected] github.com
github.com/open-telemetry/opentelemetry-python/commit/faa72dae511ae64a7b... [email protected] github.com
github.com/open-telemetry/opentelemetry-python/releases/tag/v1.45.2 [email protected] github.com
github.com/open-telemetry/opentelemetry-python/commit/78123a2755c907c602... [email protected] github.com
github.com/open-telemetry/opentelemetry-python/pull/5818 [email protected] github.com
github.com/open-telemetry/opentelemetry-python/pull/5856 [email protected] github.com
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