CVE-2026-48504 OpenTelemetry Rust: Unbounded memory allocation in W3C Baggage propagation

Medium 5.3 Published 17 Jul 2026 Updated 20 Jul 2026

Attackers can cause resource exhaustion in services using OpenTelemetry Rust by sending oversized W3C Baggage headers, leading to increased CPU and memory usage.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-48504?

CVE-2026-48504 is a medium-severity denial of service vulnerability in open-telemetry opentelemetry-rust, published on 17 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

OpenTelemetry Rust is the Rust OpenTelemetry implementation. In 0.32.0 and earlier, BaggagePropagator::extract_with_context in opentelemetry_sdk did not enforce W3C Baggage size limits before parsing an inbound baggage header, so a large attacker-controlled header could cause unnecessary CPU work and short-lived heap allocations while parsing entries later discarded by the SDK's baggage storage limits. Services that accept untrusted inbound propagation headers may experience increased per-request resource usage when processing oversized baggage headers. This issue is fixed in version 0.32.1.

Weakness: CWE-770

Which versions are affected by CVE-2026-48504?

2 open source packages ship an affected version, including opentelemetry_sdk.

Package	Affected	Fixed in
`opentelemetry_sdk` crates.io	All versions	`0.32.1`
`opentelemetry_sdk` crates.io	All versions	`0.32.1`

How do I fix CVE-2026-48504?

Upgrade opentelemetry_sdk to 0.32.1 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-2026-48504 being exploited?

There is no known exploitation of CVE-2026-48504 in the wild and no public exploit code.

Sources

Also known as GHSA-w9wp-h8wv-79jx, MINI-3v73-q5m6-3924, MINI-45rf-p35g-c9p2, MINI-7x42-3339-69rw, MINI-hq6r-8qqj-xrcm, MINI-j2c4-qgxm-r5x8 and 2 more.