OpenTelemetry Python: Unbounded tracestate parsing in opentelemetry-api

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-114603: 0.49% estimated exploitation activity in the next 30 days; percentile 41.99 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary TraceState.fromheader splits the inbound W3C tracestate header with a regular expression that starts with an unbounded optional-whitespace run, and no length limit is applied first. A run of spaces or tabs that is not followed by a comma costs O(N²) CPU. A single unauthenticated request with a ~100 KB tracestate keeps the handling worker busy for ~6 s (spaces) to ~12 s (tabs); under an asyncio server it blocks every other connection for that time. Affected component / version - Package: opentelemetry-api (pip) — opentelemetry/trace/span.py (TraceState.fromheader), reached from opentelemetry/trace/propagation/tracecontext.py (TraceContextTextMapPropagator.extract). - Confirmed in main (5e8083e8) and in the v1.44.0 and v1.45.0 tags; the same pattern is present back to v1.0.0 (introduced by #1599, March 2021). Not exhaustively verified against every release in between. - Reachable with the default propagators (OTELPROPAGATORS defaults to tracecontext,baggage) from any server…

Published by the source

22 Oct 2026, 16:22 UTC

Last modified by the source

22 Oct 2026, 16:30 UTC

Source last checked

26 Oct 2026, 13:55 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-xcq7-p3pf-p88h

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-xcq7-p3pf-p88h

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-xcq7-p3pf-p88h

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# Patch Next advisory brief: CVE-2026-114603

Advisory: OpenTelemetry Python: Unbounded tracestate parsing in opentelemetry-api
IDs: CVE-2026-114603, GHSA-xcq7-p3pf-p88h
Record: https://patchnext.com/advisories/cve-2026-114603 (revision 3, source checked 26 Oct 2026, 13:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: opentelemetry-api 1.45.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI opentelemetry-api: affected <= 1.45.0; fixed in 1.45.1

## Suggested inspection (read-only)
- `python -m pip show opentelemetry-api`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on opentelemetry-api.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-xcq7-p3pf-p88h (GitHub-reviewed advisory GHSA-xcq7-p3pf-p88h lists affected ranges: PyPI opentelemetry-api >=0 <=1.45.0)
- Verified: https://osv.dev/vulnerability/GHSA-xcq7-p3pf-p88h (OSV record GHSA-xcq7-p3pf-p88h lists affected ranges: PyPI opentelemetry-api >=0 <1.45.1 (fixed))

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