# CVE-2026-27878: Tempo TraceQL query with exemplar hint could result in unbounded memory usage

> An authenticated user can cause an out-of-memory crash in Grafana Tempo by submitting a TraceQL query with a large exemplar hint.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Jun 2026
- **Updated:** 27 Aug 2026
- **Also known as:** ECHO-f767-d344-5c3e, GHSA-6xff-cpcq-vpw2, GO-2026-6325, MINI-2w7p-cc6j-3prm, MINI-3pwp-mrjg-5cpj, MINI-5pp6-48x6-4xr9, MINI-64g3-6mm4-85m7, MINI-8cpc-m34m-2fm9, MINI-9q62-5j3m-xc4g, MINI-9rxx-7f55-v4rp, MINI-c7hh-g5wv-hfv5, MINI-c8q8-82r6-m65v, MINI-cjwf-2r4v-3prj, MINI-cmxg-g4xg-6cr7, MINI-f5fm-qfv4-rmhp, MINI-q6gh-6qv2-5c3m, MINI-v8f9-695f-23vg, MINI-vwhw-5gmj-6hgq, MINI-wcjx-3rm7-2hh8

## What is CVE-2026-27878?

CVE-2026-27878 is a medium-severity denial of service vulnerability in Grafana Enterprise Traces (GET), published on 19 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-27878?

3 open source packages ship an affected version, including github.com/grafana/tempo. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/grafana/tempo` | Go | All versions | 1.5.1-0.20260303204923-b13f74291d48 |
| `github.com/grafana/tempo` | Go | All versions | 1.5.1-0.20260303204923-b13f74291d48 |
| `github.com/grafana/tempo` | Go | All versions | 1.5.1-0.20260303204923-b13f74291d48 |

Products: Grafana Tempo.

## How do I fix CVE-2026-27878?

Upgrade github.com/grafana/tempo to 1.5.1-0.20260303204923-b13f74291d48 or later.

## Is CVE-2026-27878 being exploited?

There is no known exploitation of CVE-2026-27878 in the wild and no public exploit code.

## Other vulnerabilities in Grafana Enterprise Traces (GET)

- [CVE-2026-21728](https://insights.sbomify.com/CVE-2026-21728/): Tempo query limit results in unbounded memory allocation (high 7.5)
- [CVE-2026-28377](https://insights.sbomify.com/CVE-2026-28377/): S3 SSE-C Encryption Key Exposed in Plaintext via Config Endpoint (CVE-2025-41118 Pattern) (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-27878 and fix it if it is affected.

What it is: CVE-2026-27878 is a medium-severity denial of service vulnerability in Grafana Enterprise Traces (GET), published on 19 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-27878 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/grafana/tempo (Go): affected all versions; fixed in 1.5.1-0.20260303204923-b13f74291d48
- github.com/grafana/tempo (Go): affected all versions; fixed in 1.5.1-0.20260303204923-b13f74291d48
- github.com/grafana/tempo (Go): affected all versions; fixed in 1.5.1-0.20260303204923-b13f74291d48

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-27878/ (Markdown: https://insights.sbomify.com/CVE-2026-27878/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-27878
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-27878
- OSV: https://osv.dev/vulnerability/CVE-2026-27878

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-27878/
Summaries are generated and may contain mistakes; the official description above is the record.