OpenTelemetry-Go: multi-value baggage header extraction causes excessive allocations (remote dos amplification)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-29181: 0.79% estimated exploitation activity in the next 30 days; percentile 56.32 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

multi-value baggage: header extraction parses each header field-value independently and aggregates members across values. this allows an attacker to amplify cpu and allocations by sending many baggage: header lines, even when each individual value is within the 8192-byte per-value parse limit. severity HIGH (availability / remote request amplification) relevant links - repository: https://github.com/open-telemetry/opentelemetry-go - pinned callsite: https://github.com/open-telemetry/opentelemetry-go/blob/1ee4a4126dbdd1bc79e9fae072fa488beffac52a/propagation/baggage.go#L58 vulnerability details pins: open-telemetry/opentelemetry-go@1ee4a4126dbdd1bc79e9fae072fa488beffac52a as-of: 2026-02-04 policy: direct (no program scope provided) callsite: propagation/baggage.go:58 (extractMultiBaggage) attacker control: inbound HTTP request headers (many baggage field-values) → propagation.HeaderCarrier.Values("baggage") → repeated baggage.Parse + member aggregation root cause extractMultiBaggage…

Published by the source

7 Apr 2026, 20:12 UTC

Last modified by the source

24 Apr 2026, 20:04 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-mh2q-q3fh-2475

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# Patch Next advisory brief: CVE-2026-29181

Advisory: OpenTelemetry-Go: multi-value `baggage` header extraction causes excessive allocations (remote dos amplification)
IDs: CVE-2026-29181, GHSA-mh2q-q3fh-2475
Record: https://patchnext.com/advisories/cve-2026-29181 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: go.opentelemetry.io/otel 1.41.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go go.opentelemetry.io/otel: affected >= 1.36.0, <= 1.40.0; fixed in 1.41.0

## Suggested inspection (read-only)
- Go go.opentelemetry.io/otel: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on go.opentelemetry.io/otel.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-mh2q-q3fh-2475 (GitHub-reviewed advisory GHSA-mh2q-q3fh-2475 lists affected ranges: Go go.opentelemetry.io/otel >=1.36.0 <=1.40.0)

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