OpenTelemetry 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.
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Affected Vendors & Products
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History
Sat, 14 Nov 2026 05:00:00 +0000
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Opentelemetry
Opentelemetry opentelemetry-python |
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Opentelemetry
Opentelemetry opentelemetry-python |
Thu, 12 Nov 2026 22:30:00 +0000
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| Description | OpenTelemetry 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. | |
| Title | OpenTelemetry Python: Denial of service through quadratic-time traceparent parsing in opentelemetry-api | |
| Weaknesses | CWE-1333 | |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-11-12T22:24:22.023Z
Updated: 2026-11-13T00:37:26.148Z
Reserved: 2026-11-10T21:12:01.228Z
Link: CVE-2026-126360
No data.
Status : Received
Published: 2026-11-13T00:20:11.410
Modified: 2026-11-13T02:18:52.200
Link: CVE-2026-126360
No data.
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