OpenTelemetry Rust: Unbounded memory allocation in W3C Baggage propagation

published 2026-06-25 4 mo ago modified 2026-10-24 15 d ago also GHSA-w9wp-h8wv-79jx , EUVD-2026-45314

cvss: 5.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits: 0; none known

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.

Patch / fix

fixed in 1 links 1

crates.io opentelemetry_sdk 0.32.1

github.com/open-telemetry/opentelemetry-rust@a389ca6 commit

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 3 mo ago (2026-07-20)

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
GitHub	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem	package	affected	fixed in
crates.io	opentelemetry_sdk	<0.32.1	0.32.1

Affected products

open-telemetry opentelemetry-rust

Classification

Weakness

CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary