CVE-2026-21728 Tempo query limit results in unbounded memory allocation

What is CVE-2026-21728?

CVE-2026-21728 is a high-severity denial of service vulnerability in Grafana Enterprise Traces (GET), published on 24 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Tempo queries with large limits can cause large memory allocations which can impact the availability of the service, depending on its deployment strategy.

Mitigation can be done by setting max_result_limit in the search config, e.g. to 262144 (2^18). Alternatively, automatically restart the service.

Weakness: CWE-770, CWE-400

Which versions are affected by CVE-2026-21728?

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

Products include Grafana Tempo.

How do I fix CVE-2026-21728?

Upgrade github.com/grafana/tempo to a fixed version for your release line: 2.8.4, 2.10.2 or 2.9.2.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-21728 being exploited?

There is no known exploitation of CVE-2026-21728 in the wild and no public exploit code.

Other vulnerabilities in Grafana Enterprise Traces (GET)

• CVE-2026-28377 S3 SSE-C Encryption Key Exposed in Plaintext via Config Endpoint (CVE-2025-41118 Pattern) High 7.5
• CVE-2026-27878 Tempo TraceQL query with exemplar hint could result in unbounded memory usage Medium 6.5

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as CLEANSTART-2026-DW50999, CLEANSTART-2026-IZ25531, CLEANSTART-2026-NL77468, CLEANSTART-2026-XP22570, ECHO-854a-eb69-2b5a, GHSA-p4r4-xvrq-gvmc and 19 more.