Releases

Prometheus v3.13.0 is an LTS release leading with a HIGH-severity credential-forwarding fix (CVE-2025-4673, CVE-2023-45289) and a MEDIUM XSS fix (CVE-2026-44990), alongside four breaking changes to pagination tokens, path resolution, PromQL duration function names, and license file packaging, plus a broad set of new features and performance improvements.

• securityHIGH: Credentials no longer forwarded on cross-host redirects

  Credentials (Authorization header, basic auth, bearer token, OAuth2, and configured headers) are no longer forwarded when following a redirect to a different host. This affects scraping, remote read/write, alerting, and service discovery where credentials are configured and cross-host redirects occur. Tracked as CVE-2025-4673 and CVE-2023-45289; driven by upgrading prometheus/common from v0.68.x to v0.69.0. Review any targets or endpoints that rely on redirects, as credentials will now be dropped silently on host change.

• securityMEDIUM: XSS fix in UI dependency (CVE-2026-44990)

  sanitize-html was bumped to fix a cross-site scripting vulnerability (CVE-2026-44990) in the Prometheus UI. No configuration change needed; upgrade to v3.13.0.

• breakingPagination token algorithm changed from SHA-1 to SHA-256

  Rule group pagination tokens now use SHA-256 instead of SHA-1. Any client or tooling that stores or compares pagination tokens across versions will see different token values after upgrade.

• breaking--http.config.file relative path resolution changed

  Relative file paths inside the file passed to --http.config.file are now resolved relative to that config file's own directory, not its parent directory. If you use relative paths in that config, verify they still resolve correctly after upgrading.

• breakingDuration-expression functions min()/max() renamed to min_of()/max_of()

  If you use the experimental-duration-expr feature flag, the PromQL duration functions min() and max() have been renamed to min_of() and max_of(). Update any queries or rules that use the old names.

• breakingnpm_licenses.tar.bz2 removed; licenses now at /assets/third-party-licenses.txt

  npm_licenses.tar.bz2 is no longer shipped in release tarballs or container images. Third-party npm license text is now embedded in the binary and served at /assets/third-party-licenses.txt. Any automation that extracted that archive needs updating.

Prometheus v3.5.4 is a security-focused patch: fixes a secret-exposure bug in STACKIT SD and bumps several Go/UI dependencies to patch known CVEs. Upgrade promptly.

• securityRotate STACKIT SD credentials if you use that SD

  The /-/config endpoint was exposing STACKIT service discovery secrets in plaintext. If your Prometheus instance uses STACKIT SD and /-/config was reachable by anyone other than admins, assume those credentials are compromised and rotate them. Upgrade to v3.5.4 immediately, then restrict access to /-/config behind authentication.

• securityUpgrade to patch three Go CVEs in golang.org/x/net and OpenTelemetry

  GO-2026-5026, GO-2026-4918, and GO-2026-4985 are addressed by bumping golang.org/x/net to v0.55.0 and OpenTelemetry to v1.43.0. If you run Prometheus exposed to untrusted network traffic, this upgrade should not wait for your next maintenance window.

• enhancementghcr.io image publishing available as an alternative pull source

  Prometheus images are now also on ghcr.io. If your environment has rate-limit or access issues with Docker Hub, you can switch your image pull source to ghcr.io/prometheus/prometheus without waiting for a feature release.

Prometheus 3.12.0 ships two security patches (Remote Write DoS, STACKIT SD secret leak), fixes a WAL race in Agent mode, and cuts TSDB range query CPU with a quadratic-to-constant head chunk lookup fix.

• securityPatch two security fixes now — especially if using STACKIT SD

  Two CVEs patched in this release. First: Remote Write now rejects snappy-compressed payloads where the declared decoded size exceeds 32 MB — this closes a DoS vector against your remote-write receiver endpoint. Second: STACKIT SD was leaking secrets in plaintext via the `/-/config` endpoint (GHSA-39j6-789q-qxvh). If you use STACKIT SD, rotate any credentials that may have been exposed before upgrading.

• breakingAgent mode WAL race and remote_write panic bug fixed — upgrade Agent deployments

  A race condition in the agent appender could produce duplicate in-memory series and duplicate WAL records when concurrent appends target the same label set. If you run Prometheus in Agent mode under high write concurrency, this bug could silently corrupt your WAL. Upgrade to 3.12.0 to fix it. Also, `remote_write` queue_config fields are now validated at load time — misconfigurations that previously caused silent runtime panics will now fail at startup, which is the right behavior but means you should test configs before rolling out.

• enhancementTSDB range query CPU cut and auto-reload-config is now stable

  TSDB head chunk lookup in range queries drops from quadratic to constant time, and mmap operations now skip series that don't need work. At production scale with large head chunks, this can meaningfully cut CPU. No config changes needed — just upgrade. Separately, `auto-reload-config` is now stable (no longer experimental), so you can drop any caveats around it in runbooks.

Prometheus v3.11.3 patches three security vulnerabilities: a credential leak, a DoS vector via malformed snappy payloads, and a stored XSS in the classic UI.

• securityRotate AzureAD client secrets if /-/config was accessible

  If you use AzureAD remote write and the /-/config endpoint was reachable by anyone other than trusted admins, treat your client_secret as compromised. Rotate it in Azure AD immediately, then upgrade to v3.11.3. Also audit who has access to that endpoint — it should never be public-facing.

• securityUpgrade immediately if remote-read is enabled and exposed

  The snappy decode vulnerability lets an attacker send a crafted request with an inflated declared length, potentially exhausting memory. If your Prometheus remote-read endpoint is reachable from outside your trust boundary, this is a real DoS risk. Upgrade to v3.11.3 as soon as possible — there's no config-level workaround short of disabling remote-read entirely.

• securityAssess XSS exposure if you still run the classic UI

  The stored XSS in the old UI heatmap affects any deployment where users can influence label values (e.g., via instrumented applications) and other users view those charts. If you've already migrated to the new UI, you're not affected. If you haven't, upgrade now — or at minimum restrict UI access to trusted users until you do.

Prometheus v3.5.3 is a security-only release patching four vulnerabilities: credential exposure, two snappy decompression bombs, and a stored XSS in the legacy UI.

• securityRotate AzureAD client_secret immediately if /-/config was exposed

  Any Prometheus instance using AzureAD remote write had its OAuth client_secret visible in plaintext at the /-/config endpoint. If that endpoint was reachable by untrusted users or scraped by monitoring tools, treat the secret as compromised. Rotate it in Azure AD, update your Prometheus config, and then upgrade to v3.5.3. After upgrading, restrict /-/config access via --web.enable-admin-api controls or a reverse proxy allowlist.

• securityUpgrade now if you accept remote-read or remote-write from untrusted sources

  Both remote-read and remote-write endpoints were vulnerable to decompression bomb attacks — a crafted snappy request with an inflated declared size could exhaust memory. If your Prometheus is internet-facing or accepts data from multiple tenants, this is a denial-of-service risk. Upgrade to v3.5.3 immediately. There is no config-level workaround; the fix is in the code.

• securityPatch stored XSS if anyone uses the legacy UI with untrusted label values

  The old UI heatmap rendered 'le' label values without escaping, allowing stored XSS. If your users browse the legacy UI and your metrics include 'le' labels sourced from external or user-controlled systems, malicious JavaScript could execute in their browsers. Upgrade to v3.5.3. As a short-term measure, direct users to the new UI instead.

Prometheus v3.11.2 patches a stored XSS vulnerability (CVE-2026-40179) in the web UI, plus two Consul SD fixes. Upgrade immediately if your UI is exposed.

• securityPatch CVE-2026-40179 immediately if your Prometheus UI is reachable

  A stored XSS can be triggered by crafted metric names or label values — meaning any scrape target you ingest data from could potentially inject malicious scripts into your UI. If your Prometheus endpoint is accessible to users beyond the ops team (internal dashboards, federated setups), treat this as urgent. Upgrade to v3.11.2 now. If you can't upgrade immediately, restrict UI access via network policy or auth proxy until you can.

• breakingVerify Consul SD behavior after the Health API filter fix

  The filter parameter was previously applied incorrectly to the Consul Health API. After upgrading, your Consul service discovery results may change if you were relying on that filter — intentionally or not. Review your Consul SD configs and validate that the services being scraped post-upgrade match your expectations before rolling out to production.

• enhancementUse `health_filter` in Consul SD to reduce noise from unhealthy services

  The new `health_filter` field lets you filter Consul Health API responses directly at the SD layer. If you've been working around this with relabeling rules to drop unhealthy instances, you can now clean that up. Set `health_filter` to `healthy` in your Consul SD config to only scrape passing services and reduce unnecessary target churn.

Prometheus v3.5.2 was released, but the published notes are too brief to summarize. See the original release notes for details.

Prometheus v3.11.1 was released, but the published notes are too brief to summarize. See the original release notes for details.

Prometheus v3.11.0 ships significant new discovery capabilities, TSDB experimental features, and a critical retention bug fix that could cause data to be kept 1,000,000x longer than configured.

• breakingFix TSDB retention unit bug before your disk fills up

  A unit mismatch in the config file parser caused `storage.tsdb.retention.time` to be interpreted as 1,000,000x the intended value. If you set retention via the config file (not CLI flags), your TSDB may be holding far more data than expected. Upgrade to 3.11.0 immediately and verify disk usage post-upgrade. Also note: CLI flag values are now the fallback when retention is removed from config, so review your configuration carefully.

• breakingMigrate Hetzner hcloud SD label references before July 2026

  `__meta_hetzner_datacenter` and `__meta_hetzner_hcloud_datacenter_location*` labels are deprecated for hcloud roles and will stop working after July 1, 2026. Audit all relabeling configs and recording rules that reference these labels. Replace with `__meta_hetzner_hcloud_location` and `__meta_hetzner_hcloud_location_network_zone`. The robot role keeps the old label for backward compatibility.

• enhancementCap TSDB disk usage with retention.percentage

  The new `storage.tsdb.retention.percentage` setting lets you define a maximum percentage of available disk that TSDB can use. This is a cleaner safety net than estimating byte-based retention limits, especially in environments with variable data volumes. Consider pairing it with the existing time-based retention rather than replacing it — both constraints apply.

Prometheus 3.10.0 introduces distroless Docker images for enhanced security, new PromQL fill() functions for handling missing data, and numerous performance improvements across query execution and TSDB operations.

• enhancementConsider migrating to distroless images for production

  The new distroless variant provides better security with minimal attack surface and uses proper nonroot UID/GID 65532. Plan migration by adjusting volume ownership and permissions - existing named volumes require ownership changes, and bind mounts may need permission adjustments depending on your setup.

• enhancementOptimize memory usage with stale series compaction

  Enable experimental `stale_series_compaction_threshold` in your config to automatically compact stale series in memory, reducing memory footprint for workloads with high series churn. Start with conservative thresholds and monitor memory usage patterns.

• enhancementBuild custom Prometheus binaries for resource optimization

  Use new build tags `remove_all_sd` and `enable_<sd name>_sd` to create smaller Prometheus binaries containing only the service discovery mechanisms you actually use, reducing binary size and potential attack surface in containerized deployments.