opentelemetry-js: Unbounded memory allocation in W3C Baggage propagation

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

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.

Source published

22 Jun 2026 16:52:54 UTC

Source modified

23 Jun 2026 16:11:07 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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.

Source published

Jun 22, 2026, 4:52:54 PM (timezone not stated)

Source modified

Jun 23, 2026, 4:11:07 PM (timezone not stated)

Observed here

7 Nov 2026 12:29:05 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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.

Source published

22 Jun 2026 18:16:47 UTC

Source modified

25 Oct 2026 23:10:00 UTC

Observed here

27 Oct 2026 14:13:32 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

## 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](https://www.w3.org/TR/baggage/#limits) - opentelemetry-java: [GHSA-rcgg-9c38-7xpx](https://github.com/open-telemetry/opentelemetry-java/security/advisories/GHSA-rcgg-9c38-7xpx) - opentelemetry-go: [GHSA-mh2q-q3fh-2475](https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-mh2q-q3fh-2475) ## Credit Reported by tonghuaroot.

Source published

15 Jun 2026 20:38:30 UTC

Source modified

10 Sep 2026 03:50:48 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Publisher rating · MODERATE