CVE-2026-48504

BaggagePropagator::extract_with_context in opentelemetry_sdk did not enforce the W3C Baggage size limits before parsing an inbound baggage header. A large attacker-controlled header could cause unnecessary CPU work and short-lived heap allocations while parsing entries that would later be discarded by the SDK's baggage storage limits.

The SDK now applies limits aligned with the W3C Baggage limits:

• 64 list-members
• 8192 bytes total

Resources

• W3C Baggage limits: https://www.w3.org/TR/baggage/#limits
  • Related OpenTelemetry Java advisory: https://github.com/open-telemetry/opentelemetry-java/security/advisories/GHSA-rcgg-9c38-7xpx
  • Related OpenTelemetry Go advisory: https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-mh2q-q3fh-2475
  • CVE-2026-48504

Credit

tonghuaroot

Services that accept untrusted inbound propagation headers may experience increased per-request resource usage when processing oversized baggage headers. This can contribute to denial-of-service risk, especially when application or transport-level header limits are absent or configured above the W3C Baggage limits.

The impact is limited to availability. This issue does not expose telemetry data, modify telemetry data, or allow code execution.

The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.

CVE-2026-48504 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.32.1); upgrading removes the vulnerable code path.

Kodem intelligence

Upgrade opentelemetry_sdk to version 0.32.1 or later.

Version 0.32.1 rejects baggage header values larger than 8192 bytes and limits extraction to the first 64 list-members.

Workarounds

If upgrading immediately is not possible, reject or limit inbound baggage headers larger than 8192 bytes before invoking OpenTelemetry propagation extraction. This can be enforced at a proxy, gateway, middleware layer, or custom carrier boundary.

1. What is CVE-2026-48504? CVE-2026-48504 is a medium-severity allocation of resources without limits or throttling vulnerability in opentelemetry_sdk (rust), affecting versions <= 0.32.0. It is fixed in 0.32.1. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
2. How severe is CVE-2026-48504? CVE-2026-48504 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of opentelemetry_sdk are affected by CVE-2026-48504? opentelemetry_sdk (rust) versions <= 0.32.0 is affected.
4. Is there a fix for CVE-2026-48504? Yes. CVE-2026-48504 is fixed in 0.32.1. Upgrade to this version or later.
5. Is CVE-2026-48504 exploitable, and should I be worried? Whether CVE-2026-48504 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-48504 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-48504? Upgrade opentelemetry_sdk to 0.32.1 or later.