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CVE-2026-50271

dd-trace-py: Improper parsing of W3C baggage headers may lead to DoS

7.5 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.79%Up 0.7 points since Jun 12, 2026
90%50%10%1%

What each source reports

CVE List Score used 7.5

dd-trace-py: Improper parsing of W3C baggage headers may lead to DoS

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.

Record
CVE-2026-50271
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-770
Updated
2026-11-02
EUVDEUVD-2026-45329 7.5

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.

Record
EUVD-2026-45329
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-mw54-j2v2-42hr 7.5

dd-trace-py: Improper parsing of W3C baggage headers may lead to DoS

Impact

Datadog tracing libraries that implement W3C baggage propagation parse incoming baggage HTTP headers without enforcing item-count or byte-size limits on the extract path. The DD_TRACE_BAGGAGE_MAX_ITEMS (default 64) and DD_TRACE_BAGGAGE_MAX_BYTES (default 8192) limits were applied only to baggage injection, not extraction. 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). The tracer allocates a hash-map entry for each pair on every request, causing unbounded CPU and memory consumption and enabling a remote Denial of Service against any HTTP service that has the baggage propagation style enabled. The baggage propagation style is enabled by default in most affected tracers, so any internet-facing service that has been instrumented with an affected tracer version is exposed unless the propagation style has been explicitly narrowed.

Patches

This is resolved in version 4.8.2 and later of the dd-trace-py library

Workarounds

If users cannot upgrade immediately:

  1. Disable baggage extraction by removing baggage from DD_TRACE_PROPAGATION_STYLE (or DD_TRACE_PROPAGATION_STYLE_EXTRACT if set independently).
  2. Cap the maximum HTTP request header size at an upstream proxy or web server (for example, Apache LimitRequestFieldSize, Nginx large_client_header_buffers, Envoy max_request_headers_kb).

Resources

Related upstream advisories: opentelemetry-go GHSA-mh2q-q3fh-2475 opentelemetry-dotnet GHSA-g94r-2vxg-569j

Record
GHSA-mw54-j2v2-42hr
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400, CWE-770
Updated
2026-11-02
NVD 7.5

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.

Record
CVE-2026-50271
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-770
Updated
2026-11-02
OSV 7.5

dd-trace-py: Improper parsing of W3C baggage headers may lead to DoS

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.

Record
CVE-2026-50271
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-770
Updated
2026-11-02
OSVGHSA-mw54-j2v2-42hr 7.5

dd-trace-py: Improper parsing of W3C baggage headers may lead to DoS

Impact

Datadog tracing libraries that implement W3C baggage propagation parse incoming baggage HTTP headers without enforcing item-count or byte-size limits on the extract path. The DD_TRACE_BAGGAGE_MAX_ITEMS (default 64) and DD_TRACE_BAGGAGE_MAX_BYTES (default 8192) limits were applied only to baggage injection, not extraction. 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). The tracer allocates a hash-map entry for each pair on every request, causing unbounded CPU and memory consumption and enabling a remote Denial of Service against any HTTP service that has the baggage propagation style enabled. The baggage propagation style is enabled by default in most affected tracers, so any internet-facing service that has been instrumented with an affected tracer version is exposed unless the propagation style has been explicitly narrowed.

Patches

This is resolved in version 4.8.2 and later of the dd-trace-py library

Workarounds

If users cannot upgrade immediately:

  1. Disable baggage extraction by removing baggage from DD_TRACE_PROPAGATION_STYLE (or DD_TRACE_PROPAGATION_STYLE_EXTRACT if set independently).
  2. Cap the maximum HTTP request header size at an upstream proxy or web server (for example, Apache LimitRequestFieldSize, Nginx large_client_header_buffers, Envoy max_request_headers_kb).

Resources

Related upstream advisories: opentelemetry-go GHSA-mh2q-q3fh-2475 opentelemetry-dotnet GHSA-g94r-2vxg-569j

Record
GHSA-mw54-j2v2-42hr
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400, CWE-770
Updated
2026-11-02
OSVPYSEC-2026-3461 7.5

dd-trace-py: Improper parsing of W3C baggage headers may lead to DoS

Impact

Datadog tracing libraries that implement W3C baggage propagation parse incoming baggage HTTP headers without enforcing item-count or byte-size limits on the extract path. The DD_TRACE_BAGGAGE_MAX_ITEMS (default 64) and DD_TRACE_BAGGAGE_MAX_BYTES (default 8192) limits were applied only to baggage injection, not extraction. 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). The tracer allocates a hash-map entry for each pair on every request, causing unbounded CPU and memory consumption and enabling a remote Denial of Service against any HTTP service that has the baggage propagation style enabled. The baggage propagation style is enabled by default in most affected tracers, so any internet-facing service that has been instrumented with an affected tracer version is exposed unless the propagation style has been explicitly narrowed.

Patches

This is resolved in version 4.8.2 and later of the dd-trace-py library

Workarounds

If users cannot upgrade immediately:

  1. Disable baggage extraction by removing baggage from DD_TRACE_PROPAGATION_STYLE (or DD_TRACE_PROPAGATION_STYLE_EXTRACT if set independently).
  2. Cap the maximum HTTP request header size at an upstream proxy or web server (for example, Apache LimitRequestFieldSize, Nginx large_client_header_buffers, Envoy max_request_headers_kb).

Resources

Related upstream advisories: opentelemetry-go GHSA-mh2q-q3fh-2475 opentelemetry-dotnet GHSA-g94r-2vxg-569j

Record
PYSEC-2026-3461
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVROOT-APP-PYPI-CVE-2026-50271 No score

CVE-2026-50271 in ddtrace - Patched by Root

Root has patched CVE-2026-50271 in the ddtrace package for Root:PyPI. Multiple fixed versions available.

Record
ROOT-APP-PYPI-CVE-2026-50271
Updated
2026-11-03

Affected products

Affected packages

Affected packages
PackageAffectedFixed
ddtrace
PyPI
 before 4.8.2
4.8.2
ddtrace
PyPI
 before 4.8.2, plus listed versions
0.10.00.10.10.11.00.11.10.12.0
Show 45 moreShow less
0.12.10.13.00.13.10.14.00.14.10.15.00.16.00.17.00.17.10.18.00.19.00.20.00.20.10.20.20.20.30.20.40.21.00.21.10.22.00.23.00.24.00.25.00.26.00.27.00.27.10.28.00.29.00.30.00.30.10.30.20.31.00.32.00.32.10.32.20.33.00.34.00.34.10.34.20.35.00.35.10.35.20.36.00.36.10.36.20.36.3
4.8.2
ddtrace
Root:PyPI
 before 3.2.0+aikido.2
3.2.0+aikido.22.1.3+aikido.14.7.1+aikido.14.8.0+aikido.11.7.3+aikido.13.19.5+aikido.1

History

History
RecordedChangedSources
affectedOSV
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-50271 is a high vulnerability (CVSS 7.5) in Datadog Dd-trace-py, published July 15, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.79%, the 56th percentile. Fixed in ddtrace 4.8.2.

References

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Left out here: 724 versions. The JSON record has them.

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