opentelemetry-go's baggage parsing no longer caps raw header length

Exploitation

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

CVSS

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

EPSS

• CVE-2026-41178: 0.34% estimated exploitation activity in the next 30 days; percentile 27.02 (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.

Summary https://github.com/open-telemetry/opentelemetry-go/pull/7880 removed raw-length rejection and it causes Parse to process arbitrarily large/invalid baggage headers and log errors, enabling DoS via oversized inputs. Details The commit removes the upfront baggage-string length check and the per-member size guard in parsing. Parse now walks the entire input with strings.SplitSeq and skips invalid members while continuing to process the rest. For very large or malformed baggage headers, the parser still fully tokenizes and percent-decodes each member, and errors are forwarded to the global error handler (default logging). This lets a remote client send oversized/invalid headers to trigger excessive CPU/memory work and potentially large log output before any size limit is enforced, creating a denial-of-service risk in services that do not already enforce strict header size limits. Summary: - In baggage/baggage.go, parseMember performs full parsing and PathUnescape on the entire…

Published by the source

28 May 2026, 17:04 UTC

Last modified by the source

9 Jun 2026, 11:53 UTC

Source last checked

26 Oct 2026, 15:23 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-5wrp-cwcj-q835

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# Patch Next advisory brief: CVE-2026-41178

Advisory: opentelemetry-go's baggage parsing no longer caps raw header length
IDs: CVE-2026-41178, GHSA-5wrp-cwcj-q835
Record: https://patchnext.com/advisories/cve-2026-41178 (revision 1, source checked 26 Oct 2026, 15:23 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
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/baggage 1.44.0, 1.42.0; go.opentelemetry.io/otel/propagation 1.44.0, 1.42.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go go.opentelemetry.io/otel/baggage: affected >= 1.41.0, <= 1.41.0; >= 1.43.0, <= 1.43.0; fixed in 1.44.0, 1.42.0
- Go go.opentelemetry.io/otel/propagation: affected >= 1.41.0, <= 1.41.0; >= 1.43.0, <= 1.43.0; fixed in 1.44.0, 1.42.0

## Suggested inspection (read-only)
- Go go.opentelemetry.io/otel/baggage: check the installed version with your package manager.
- Go go.opentelemetry.io/otel/propagation: 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/baggage, go.opentelemetry.io/otel/propagation.
- 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-5wrp-cwcj-q835 (GitHub-reviewed advisory GHSA-5wrp-cwcj-q835 lists affected ranges: Go go.opentelemetry.io/otel/baggage >=1.41.0 =1.43.0 =1.41.0 =1.43.0 <=1.43.0)

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