Is there a public exploit for CVE-2026-126360?

No public exploit for CVE-2026-126360 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-126360?

CVE-2026-126360 scores CVSS 5.3 (v3.1), rated medium. EPSS puts the chance of exploitation in the next 30 days at 0.00519%.

What does CVE-2026-126360 affect?

CVE-2026-126360 affects opentelemetry-api.

5.3 Medium

OpenTelemetry Python API: Denial of service through quadratic-time traceparent parsing

CVE-2026-126360

Summary TraceContextTextMapPropagator.extract() in opentelemetry-api is vulnerable to regular expression denial of service (ReDoS) when processing a specially crafted traceparent value. A malformed value containing a trace-context prefix followed by a long whitespace sequence and an embedded newline triggers quadratic-time regex backtracking. Applications that extract trace context from untrusted carriers accepting such strings can experience excessive CPU consumption and request-processing delays. When extraction runs on an asynchronous server’s event-loop thread, a single malicious message can delay unrelated requests handled by that event loop. Exposure conditions Exploitation requires attacker-controlled input to reach the affected propagator through a carrier that preserves embedded newlines and permits a sufficiently large value. Conforming HTTP header values cannot contain embedded newlines. However, OpenTelemetry carriers are not restricted to HTTP headers. JSON strings can contain escaped newlines that become newline characters after decoding. MCP request metadata is one relevant integration path: applications may extract trace context from JSON params.meta. Exposure…

Assessment

CVSS: 5.3 (v3.1)
Severity: Medium
EPSS: 0.00519% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 13 November 2026
Last updated: 13 November 2026
Affected: opentelemetry-api
Weakness: CWE-1333

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

At the source

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