CVE-2026-54285: opentelemetry-js: Unbounded memory allocation in W3C Baggage propagation
Overview
W3CBaggagePropagator.extract() in @opentelemetry/core does not enforce size limits when parsing inbound baggage HTTP headers. The W3C Baggage specification recommends a maximum of 8,192 bytes and 180 entries; these limits were only enforced on the outbound (inject()) path, not on the inbound (extract()) path. Parsing oversized baggage causes memory allocation proportional to the header size without any cap.
Impact
The practical availability impact for most Node.js deployments is limited. Node.js enforces a default --max-http-header-size of 16,384 bytes on the total combined size of all HTTP headers, constraining what an external attacker can deliver before the propagator is reached. Additionally, the header is already in memory (parsed by the HTTP layer) by the time it reaches the propagator - the additional allocation is the overhead of splitting into entry objects, not an unbounded read.
The risk is higher when transport-layer limits are absent - e.g., non-HTTP transports (messaging systems, custom TextMapGetter implementations) or deployments that have raised --max-http-header-size.
Remediation
Update @opentelemetry/core to version 2.8.0 or later. The fix enforces limits consistent with the W3C Baggage specification at the propagator level:
- Maximum total baggage size: 8,192 bytes - Maximum number of entries: 180 - Maximum per-entry size: 4,096 bytes
Headers that exceed these limits are truncated at the point the limit is reached.
Workarounds
Ensure header size limits are configured at the server or gateway level. The default Node.js HTTP header limit (16 KB) mitigates external attack vectors independently of this fix. For non-HTTP transports receiving baggage from untrusted sources, validate input size before passing it to the propagator.
References
- W3C Baggage Specification - Limits - opentelemetry-java: GHSA-rcgg-9c38-7xpx - opentelemetry-go: GHSA-mh2q-q3fh-2475
Credit
Reported by tonghuaroot.
Other sources
opentelemetry-js is the OpenTelemetry JavaScript Client. Prior to 2.8.0, W3CBaggagePropagator.extract() in @opentelemetry/core does not enforce size limits when parsing inbound baggage HTTP headers. The W3C Baggage specification recommends a maximum of 8,192 bytes and 180 entries; these limits were only enforced on the outbound (inject()) path, not on the inbound (extract()) path. Parsing oversized baggage causes memory allocation proportional to the header size without any cap. This vulnerability is fixed in 2.8.0.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/@opentelemetry/coreto a version that resolves this vulnerability.Fixed in 2.8.0 - Upgrade
Upgrade
@opentelemetry/coreto a version that resolves this vulnerability.Fixed in 2.8.0 - Compensating control
Ensure header size limits are configured at the server or gateway level.
- Compensating control
For non-HTTP transports receiving baggage from untrusted sources, validate input size before passing it to the propagator.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-54285?
CVE-2026-54285 has a severity rating of medium with a score of 5.3.
What is the risk associated with CVE-2026-54285?
CVE-2026-54285 presents a risk level of 27.
How do I fix CVE-2026-54285?
To fix CVE-2026-54285, ensure that the latest version of @opentelemetry/core is installed, which implements size limits for inbound baggage HTTP headers.
What software is affected by CVE-2026-54285?
CVE-2026-54285 affects the npm package @opentelemetry/core.
When was CVE-2026-54285 published?
CVE-2026-54285 was published on June 15, 2026.