CVE-2026-27878 is a medium-severity (CVSS 6.5) Uncontrolled Resource Consumption vulnerability in github.com/grafana/tempo. A fix is available for github.com/grafana/tempo — see the affected versions and patch details below.
Tempo TraceQL query with exemplar hint could result in unbounded memory usage
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-27878.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-27878 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
github.com/grafana/tempoReal-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
A TraceQL query in Grafana Tempo with a large exemplars hint value can cause the Tempo instance to allocate an excessive amount of memory, resulting in an out-of-memory crash. This could allow an authenticated user to trigger a denial of service against the Tempo service.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/grafana/tempo | all versions | 1.5.1-0.20260303204923-b13f74291d48go get github.com/grafana/tempo@v1.5.1-0.20260303204923-b13f74291d48 |
Affected Products
tempografanaDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/grafana/tempo, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/grafana/tempo to 1.5.1-0.20260303204923-b13f74291d48 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27878 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Frequently Asked Questions
Is CVE-2026-27878 in your dependencies?
Find it across Go, including transitive dependencies.