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HIGH severity

GHSA-5rv5-6h4r-h22v opentelemetry-instrumenta…

HIGHFix: open-telemetry/opentelemetry-python-contrib@6007e0c

GHSA-5rv5-6h4r-h22v is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in opentelemetry-instrumentation. A fix is available for opentelemetry-instrumentation — see the affected versions and patch details below.

opentelemetry-instrumentation Denial of Service vulnerability due to unbound cardinality metrics

Also known asCVE-2023-43810PYSEC-2026-1752
Published
Oct 2, 2023
Updated
Sep 10, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 20, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-5rv5-6h4r-h22v.

EPSS Exploitation Probability

via FIRST.org ↗
0.7%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs51th percentile — riskier than 51% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-5rv5-6h4r-h22v plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected
🐍opentelemetry-instrumentation

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

Autoinstrumentation out of the box adds the label http_method that has unbound cardinality. It leads to the server's potential memory exhaustion when many malicious requests are sent.

Details

HTTP method for requests can be easily set by an attacker to be random and long.

PoC

Send many requests with long randomly generated HTTP methods and observe how memory consumption increases during it. The app can be like this example from the official docs.

Impact

In order to be affected program has to be instrumented for HTTP handlers and does not filter any unknown HTTP methods on the level of CDN, LB, previous middleware, etc.

Proposed solution

For convenience and safe usage of this library, it should by default mark with the label UNKNOWN non-standard HTTP methods to show that such requests were made (and this way does not increase cardinality). In case someone wants to stay with the current behavior, library API should allow it. The mechanism with environment variables can be reused - introduce the variable OTEL_INSTRUMENTATION_HTTP_CAPTURE_ALL_METHODS that will allow enabling current behavior when someone really wants it.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIopentelemetry-instrumentationall versions0.41b0pip install --upgrade 'opentelemetry-instrumentation==0.41b0'

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for opentelemetry-instrumentation, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update opentelemetry-instrumentation to 0.41b0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5rv5-6h4r-h22v is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-5rv5-6h4r-h22v can be triaged on real exposure rather than presence alone.

Tailored to GHSA-5rv5-6h4r-h22v. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary Autoinstrumentation out of the box adds the label `http_method` that has unbound cardinality. It leads to the server's potential memory exhaustion when many malicious requests are sent. ### Details HTTP method for requests can be easily set by an attacker to be random and long. ### PoC Send many requests with long randomly generated HTTP methods and observe how memory consumption increases during it. The app can be like [this example from the official docs](https://opentelemetry-python-contrib.readthedocs.io/en/latest/instrumentation/flask/flask.html#id1). ### Impact In order to
O3 Security · Impact-Aware SCA

Is GHSA-5rv5-6h4r-h22v in your dependencies?

O3 Security finds GHSA-5rv5-6h4r-h22v across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-5rv5-6h4r-h22v: High 7.5 severity | O3 Security