CVE-2026-50271 dd-trace-py: Improper parsing of W3C baggage headers may lead to DoS
Remote attackers can cause denial of service in Datadog Python APM clients by sending oversized W3C baggage headers that bypass resource limits.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-50271?
CVE-2026-50271 is a high-severity denial of service vulnerability in DataDog dd-trace-py, published on 17 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-770
Which versions are affected by CVE-2026-50271?
3 open source packages ship an affected version, including ddtrace.
| Package | Affected | Fixed in |
|---|---|---|
ddtrace PyPI | All versions | 4.8.2 |
ddtrace PyPI | All versions | 4.8.2 |
ddtrace PyPI | All versions | 4.8.2 |
How do I fix CVE-2026-50271?
Upgrade ddtrace to 4.8.2 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-50271 being exploited?
There is no known exploitation of CVE-2026-50271 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-LJ45611, ECHO-3720-ec23-e2d2, GHSA-mw54-j2v2-42hr, MINI-2j8x-g7r5-fmp9, MINI-7cpj-j3j8-wr8x, MINI-7w5v-m3wj-2rch and 15 more.