GHSA-5wrp-cwcj-q835 is a medium-severity (CVSS 5.3) CWE-789 vulnerability in go.opentelemetry.io/otel/baggage. O3 Security confirms whether GHSA-5wrp-cwcj-q835 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
opentelemetry-go's baggage parsing no longer caps raw header length
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for GHSA-5wrp-cwcj-q835.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-5wrp-cwcj-q835 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 364,277 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
go.opentelemetry.io/otel/baggage🐹go.opentelemetry.io/otel/propagation🐹go.opentelemetry.io/otel/baggage🐹go.opentelemetry.io/otel/propagationReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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,parseMemberperforms full parsing andPathUnescapeon the entire member without any size guard, amplifying work for large inputs.Parseno longer checks bStr length and continues processing invalid members, so oversized/invalid headers are fully parsed instead of being rejected early. - In
propagation/baggage.go, parsing errors from attacker-controlled headers are sent to the global error handler (default logging), which can amplify oversized-input impact.
PoC
Impact
The issue is reachable through standard propagation parsing (in-scope) and can be exploited remotely to cause CPU/log amplification, but the impact is availability-only and bounded by transport header limits and configurable error handling, supporting a medium severity rather than high/critical.
baggage.Parse iterates over all list members with strings.SplitSeq and skips invalid members while continuing, without a raw-length guard. parseMember performs full parsing and PathUnescape on each member, and propagation.Baggage forwards parsing errors to the global error handler, which logs by default. A remote client can therefore send oversized/invalid baggage headers that bypass the 8KB limit for valid members, causing extra CPU work and large log output, resulting in availability/log amplification in services that accept large headers and use the default handler.
Assumptions:
- An instrumented service uses the OpenTelemetry baggage propagator for inbound request parsing.
- Attackers can send oversized or malformed baggage headers that pass the hosting server/proxy header size limits.
- The default error handler is used or logs are otherwise emitted for parse errors.
- Inbound request parsing with propagation.Baggage
- Oversized/invalid baggage headers accepted by the HTTP/gRPC stack
- Error handler not suppressing parse errors
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | go.opentelemetry.io/otel/baggage | ≥ 1.41.0&&< 1.42.0 | 1.42.0 |
| 🐹Go | go.opentelemetry.io/otel/propagation | ≥ 1.41.0&&< 1.42.0 | 1.42.0 |
| 🐹Go | go.opentelemetry.io/otel/baggage | ≥ 1.43.0&&< 1.44.0 | 1.44.0 |
| 🐹Go | go.opentelemetry.io/otel/propagation | ≥ 1.43.0&&< 1.44.0 | 1.44.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for go.opentelemetry.io/otel/baggage. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update go.opentelemetry.io/otel/baggage to 1.42.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5wrp-cwcj-q835 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-5wrp-cwcj-q835 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-5wrp-cwcj-q835. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is GHSA-5wrp-cwcj-q835 in your dependencies?
O3 detects GHSA-5wrp-cwcj-q835 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.