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Vulnerabilities

Vulnerability · CVE-2026-114603

OpenTelemetry Python: Unbounded tracestate parsing in opentelemetry-api

Published Oct 22, 2026 · catalog updated Oct 29, 2026 · Red Hat Red Hat Enterprise Linux

Last checked Nov 7, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-114603. EPSS is 0.49%. Act only if a listed version of Red Hat Red Hat Enterprise Linux is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium5.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.49%
Remediation
Version ranges on file
Affected products
PyPI opentelemetry-api · pip opentelemetry-api · pypi opentelemetry-api

## Summary splits the inbound W3C 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 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: (pip) — ( ), reached from ( ). - Confirmed in (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 ( defaults to ) from any server instrumentation that calls , for example . ## Details 1. The header reaches the parser without any length check: 2. The split pattern and the parser: tries the pattern at every offset. At each offset inside a whitespace run, consumes the rest of the run, finds no , backtracks and fails, then the engine moves one character forward and repeats. N characters × up to N steps each = O(N²). The 32-member limit never gets a chance to run because has to finish first. 3. The sibling propagator already has the missing guard: A 16 KiB header costs ≈ 0.25 s and an 8 KiB header ≈ 0.07 s. Measured cost of on one core (valid , ): the time quadruples each time N doubles (see the proof of concept). Roughly 0.06 s at 10,000 characters, 1 s at 40,000, 4 s at 80,000, 9 s at 100,000 (tabs are about 1.6× slower). Whether a server lets such a header through (header-size limits, tested): gunicorn rejects ≥ 8190 bytes (response code 431); rejects above 16 KiB (400); waitress accepts up to 256 KiB (200 KB accepted, 300 KB rejected); — the default parser with — accepted 300 KB, 1 MB, 5 MB and 20 MB headers. ## Proof of concept ### A. Show the quadratic cost (no server needed) 1. Install the API: (any version from 1.0 up to the current main

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • PyPI opentelemetry-api0 → 1.45.1
  • pip opentelemetry-api<= 1.45.0
  • pypi opentelemetry-apiversion unspecified

How to fix CVE-2026-114603

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-114603. EPSS is 0.49%. Act only if a listed version of Red Hat Red Hat Enterprise Linux is installed.

Which versions are affected?

Compare what you have installed with 0 → 1.45.1, <= 1.45.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-1333: Inefficient Regular Expression Complexity; CWE-400: Uncontrolled Resource Consumption. EPSS 0.49%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 22, 2026 · Red Hat Security Data

    Detected

    opentelemetry-api: opentelemetry-api: Denial of Service via regular expression backtracking in header parsing

  2. Oct 22, 2026 · GitHub Advisory Database

    Updated

    ## Summary splits the inbound W3C 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 keeps the handling worker busy for ~6 s (spaces) to ~12 s (tabs); under an asyncio server it blocks every other connect

  3. Oct 22, 2026 · PyPA Advisory Database

    Fix available

    opentelemetry-api fixed in 1.45.1

  4. Oct 22, 2026 · PyPA Advisory Database

    Fix available

    opentelemetry-api fixed in 1.45.1

  5. Oct 22, 2026 · PyPA Advisory Database

    Updated

    ## Summary splits the inbound W3C 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 keeps the handling worker busy for ~6 s (spaces) to ~12 s (tabs); under an asyncio server it blocks every other connect

  6. Oct 29, 2026 · NIST NVD

    Updated

    OpenTelemetry Python provides the Python API and SDK for OpenTelemetry. Prior to 1.45.1, the opentelemetry-api function TraceState.from_header in opentelemetry/trace/span.py, reached through TraceContextTextMapPropagator.extract, parses inbound W3C tracestate headers with an unbounded optional-whitespace regular expression. A malformed header containing a long run of spaces or tabs without a follo

Sources

  • CVE.orgVulnerability recordCVE-2026-114603

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-114603

    30-day exploitation probability 0.49%

    first.org
  • GitHub Advisory DatabasePackage advisoryGHSA-xcq7-p3pf-p88h

    OpenTelemetry Python: Unbounded tracestate parsing in opentelemetry-api

    github.com
  • GitLab Advisory DatabasePackage advisoryCVE-2026-114603

    TraceState.from_header 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 se

    advisories.gitlab.com
  • NIST NVDVulnerability recordCVE-2026-114603

    OpenTelemetry Python provides the Python API and SDK for OpenTelemetry. Prior to 1.45.1, the opentelemetry-api function TraceState.from_header in opentelemetry/trace/span.py, reached through TraceContextTextMapPropagator.extract, parses inbound W3C tracestate headers with an unbo

    nvd.nist.gov
  • PyPA Advisory DatabasePackage advisoryGHSA-xcq7-p3pf-p88h

    OpenTelemetry Python: Unbounded tracestate parsing in opentelemetry-api

    osv.dev
  • Red Hat Security DataVendor advisoryCVE-2026-114603

    opentelemetry-api: opentelemetry-api: Denial of Service via regular expression backtracking in header parsing

    access.redhat.com

References

Freshness

Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 7, 2026
  • NIST NVDOct 29, 2026
  • GitHub Advisory DatabaseOct 23, 2026
  • GitLab Advisory DatabaseOct 23, 2026
  • Red Hat Security DataOct 23, 2026
  • PyPA Advisory DatabaseOct 23, 2026
  • CVE.orgOct 23, 2026