diff --git a/CHANGELOG.md b/CHANGELOG.md
index 56f3e485ed9..51bf616d052 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,7 @@
 * [FEATURE] Distributor/Ingester: Implemented experimental feature to use gRPC stream connection for push requests. This can be enabled by setting `-distributor.use-stream-push=true`. #6580
 * [FEATURE] Compactor: Add support for percentage based sharding for compactors. #6738
 * [FEATURE] Querier: Allow choosing PromQL engine via header. #6777
+* [FEATURE] Config: Name validation scheme for metric and label names can be set using the config file (`name_validation_scheme`) as well as a CLI flag (`-name.validation_scheme`)
 * [ENHANCEMENT] Tenant Federation: Add a # of query result limit logic when the `-tenant-federation.regex-matcher-enabled` is enabled. #6845
 * [ENHANCEMENT] Query Frontend: Add a `cortex_slow_queries_total` metric to track # of slow queries per user. #6859
 * [ENHANCEMENT] Query Frontend: Change to return 400 when the tenant resolving fail. #6715
diff --git a/docs/configuration/config-file-reference.md b/docs/configuration/config-file-reference.md
index 2963a87348c..4294edf1f0b 100644
--- a/docs/configuration/config-file-reference.md
+++ b/docs/configuration/config-file-reference.md
@@ -68,6 +68,12 @@ Where default_value is the value to use if the environment variable is undefined
 # CLI flag: -http.prefix
 [http_prefix: <string> | default = "/api/prom"]
 
+# Validation scheme for metric and label names.
+# Set to "utf8" to allow UTF-8 characters in metric and label names.
+# Set to "legacy" to enforce strict legacy-compatible name rules.
+# CLI flag: -name.validation_scheme
+[name_validation_scheme: <legacy | utf8> | default = "legacy"]
+
 resource_monitor:
   # Comma-separated list of resources to monitor. Supported values are cpu and
   # heap, which tracks metrics from github.com/prometheus/procfs and
diff --git a/go.mod b/go.mod
index 1b88330c581..535d4c2e0ca 100644
--- a/go.mod
+++ b/go.mod
@@ -43,9 +43,9 @@ require (
 	github.com/prometheus/alertmanager v0.28.1
 	github.com/prometheus/client_golang v1.22.0
 	github.com/prometheus/client_model v0.6.2
-	github.com/prometheus/common v0.63.0
+	github.com/prometheus/common v0.65.0
 	// Prometheus maps version 2.x.y to tags v0.x.y.
-	github.com/prometheus/prometheus v0.303.1
+	github.com/prometheus/prometheus v1.99.0
 	github.com/segmentio/fasthash v1.0.3
 	github.com/sony/gobreaker v1.0.0
 	github.com/spf13/afero v1.11.0
diff --git a/go.sum b/go.sum
index 9aa18e3ac6f..f333c5a06d2 100644
--- a/go.sum
+++ b/go.sum
@@ -838,8 +838,8 @@ github.com/prometheus/common v0.4.1/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y8
 github.com/prometheus/common v0.9.1/go.mod h1:yhUN8i9wzaXS3w1O07YhxHEBxD+W35wd8bs7vj7HSQ4=
 github.com/prometheus/common v0.10.0/go.mod h1:Tlit/dnDKsSWFlCLTWaA1cyBgKHSMdTB80sz/V91rCo=
 github.com/prometheus/common v0.26.0/go.mod h1:M7rCNAaPfAosfx8veZJCuw84e35h3Cfd9VFqTh1DIvc=
-github.com/prometheus/common v0.63.0 h1:YR/EIY1o3mEFP/kZCD7iDMnLPlGyuU2Gb3HIcXnA98k=
-github.com/prometheus/common v0.63.0/go.mod h1:VVFF/fBIoToEnWRVkYoXEkq3R3paCoxG9PXP74SnV18=
+github.com/prometheus/common v0.65.0 h1:QDwzd+G1twt//Kwj/Ww6E9FQq1iVMmODnILtW1t2VzE=
+github.com/prometheus/common v0.65.0/go.mod h1:0gZns+BLRQ3V6NdaerOhMbwwRbNh9hkGINtQAsP5GS8=
 github.com/prometheus/exporter-toolkit v0.14.0 h1:NMlswfibpcZZ+H0sZBiTjrA3/aBFHkNZqE+iCj5EmRg=
 github.com/prometheus/exporter-toolkit v0.14.0/go.mod h1:Gu5LnVvt7Nr/oqTBUC23WILZepW0nffNo10XdhQcwWA=
 github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
diff --git a/pkg/cortex/cortex.go b/pkg/cortex/cortex.go
index b141adc8127..378e5a63774 100644
--- a/pkg/cortex/cortex.go
+++ b/pkg/cortex/cortex.go
@@ -14,6 +14,8 @@ import (
 	"github.com/go-kit/log/level"
 	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/model"
+	prom_config "github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/promql"
 	prom_storage "github.com/prometheus/prometheus/storage"
 	"github.com/weaveworks/common/server"
@@ -90,11 +92,12 @@ var (
 
 // Config is the root config for Cortex.
 type Config struct {
-	Target          flagext.StringSliceCSV  `yaml:"target"`
-	AuthEnabled     bool                    `yaml:"auth_enabled"`
-	PrintConfig     bool                    `yaml:"-"`
-	HTTPPrefix      string                  `yaml:"http_prefix"`
-	ResourceMonitor configs.ResourceMonitor `yaml:"resource_monitor"`
+	Target               flagext.StringSliceCSV  `yaml:"target"`
+	AuthEnabled          bool                    `yaml:"auth_enabled"`
+	PrintConfig          bool                    `yaml:"-"`
+	HTTPPrefix           string                  `yaml:"http_prefix"`
+	ResourceMonitor      configs.ResourceMonitor `yaml:"resource_monitor"`
+	NameValidationScheme string                  `yaml:"name_validation_scheme"`
 
 	ExternalQueryable prom_storage.Queryable `yaml:"-"`
 	ExternalPusher    ruler.Pusher           `yaml:"-"`
@@ -146,7 +149,7 @@ func (c *Config) RegisterFlags(f *flag.FlagSet) {
 	f.BoolVar(&c.AuthEnabled, "auth.enabled", true, "Set to false to disable auth.")
 	f.BoolVar(&c.PrintConfig, "print.config", false, "Print the config and exit.")
 	f.StringVar(&c.HTTPPrefix, "http.prefix", "/api/prom", "HTTP path prefix for Cortex API.")
-
+	f.StringVar(&c.NameValidationScheme, "name.validation_scheme", "legacy", "Validation scheme for metric and label names. Set to utf8 to allow UTF-8 characters.")
 	c.API.RegisterFlags(f)
 	c.registerServerFlagsWithChangedDefaultValues(f)
 	c.Distributor.RegisterFlags(f)
@@ -181,6 +184,11 @@ func (c *Config) RegisterFlags(f *flag.FlagSet) {
 // Validate the cortex config and returns an error if the validation
 // doesn't pass
 func (c *Config) Validate(log log.Logger) error {
+	switch c.NameValidationScheme {
+	case "", prom_config.LegacyValidationConfig, prom_config.UTF8ValidationConfig:
+	default:
+		return fmt.Errorf("invalid name validation scheme: %s", c.NameValidationScheme)
+	}
 	if err := c.validateYAMLEmptyNodes(); err != nil {
 		return err
 	}
@@ -349,7 +357,12 @@ func New(cfg Config) (*Cortex, error) {
 		}
 		os.Exit(0)
 	}
-
+	//nolint:staticcheck // SA1019: intentional use of deprecated NameValidationScheme for backward compatibility
+	if cfg.NameValidationScheme == prom_config.UTF8ValidationConfig {
+		model.NameValidationScheme = model.UTF8Validation
+	} else {
+		model.NameValidationScheme = model.LegacyValidation
+	}
 	// Swap out the default resolver to support multiple tenant IDs separated by a '|'
 	if cfg.TenantFederation.Enabled {
 		util_log.WarnExperimentalUse("tenant-federation")
diff --git a/pkg/cortex/cortex_test.go b/pkg/cortex/cortex_test.go
index 6cac224319d..8cc466932fc 100644
--- a/pkg/cortex/cortex_test.go
+++ b/pkg/cortex/cortex_test.go
@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
+	prom_config "github.com/prometheus/prometheus/config"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"github.com/weaveworks/common/server"
@@ -217,6 +218,42 @@ func TestConfigValidation(t *testing.T) {
 			},
 			expectedError: nil,
 		},
+		{
+			name: "should not fail validation for empty name validation scheme (use legacy by default)",
+			getTestConfig: func() *Config {
+				configuration := newDefaultConfig()
+				configuration.NameValidationScheme = ""
+				return configuration
+			},
+			expectedError: nil,
+		},
+		{
+			name: "should not fail validation for legacy name validation scheme",
+			getTestConfig: func() *Config {
+				configuration := newDefaultConfig()
+				configuration.NameValidationScheme = prom_config.LegacyValidationConfig
+				return configuration
+			},
+			expectedError: nil,
+		},
+		{
+			name: "should not fail validation for utf-8 name validation scheme",
+			getTestConfig: func() *Config {
+				configuration := newDefaultConfig()
+				configuration.NameValidationScheme = prom_config.UTF8ValidationConfig
+				return configuration
+			},
+			expectedError: nil,
+		},
+		{
+			name: "should fail validation for invalid name validation scheme",
+			getTestConfig: func() *Config {
+				configuration := newDefaultConfig()
+				configuration.NameValidationScheme = "invalid"
+				return configuration
+			},
+			expectedError: fmt.Errorf("invalid name validation scheme"),
+		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			err := tc.getTestConfig().Validate(nil)
diff --git a/vendor/github.com/prometheus/common/config/http_config.go b/vendor/github.com/prometheus/common/config/http_config.go
index 63809083aca..5d3f1941bb0 100644
--- a/vendor/github.com/prometheus/common/config/http_config.go
+++ b/vendor/github.com/prometheus/common/config/http_config.go
@@ -225,7 +225,7 @@ func (u *URL) UnmarshalJSON(data []byte) error {
 // MarshalJSON implements the json.Marshaler interface for URL.
 func (u URL) MarshalJSON() ([]byte, error) {
 	if u.URL != nil {
-		return json.Marshal(u.URL.String())
+		return json.Marshal(u.String())
 	}
 	return []byte("null"), nil
 }
@@ -251,7 +251,7 @@ func (o *OAuth2) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	if err := unmarshal((*plain)(o)); err != nil {
 		return err
 	}
-	return o.ProxyConfig.Validate()
+	return o.Validate()
 }
 
 // UnmarshalJSON implements the json.Marshaler interface for URL.
@@ -260,7 +260,7 @@ func (o *OAuth2) UnmarshalJSON(data []byte) error {
 	if err := json.Unmarshal(data, (*plain)(o)); err != nil {
 		return err
 	}
-	return o.ProxyConfig.Validate()
+	return o.Validate()
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -604,8 +604,8 @@ func NewRoundTripperFromConfigWithContext(ctx context.Context, cfg HTTPClientCon
 		// The only timeout we care about is the configured scrape timeout.
 		// It is applied on request. So we leave out any timings here.
 		var rt http.RoundTripper = &http.Transport{
-			Proxy:                 cfg.ProxyConfig.Proxy(),
-			ProxyConnectHeader:    cfg.ProxyConfig.GetProxyConnectHeader(),
+			Proxy:                 cfg.Proxy(),
+			ProxyConnectHeader:    cfg.GetProxyConnectHeader(),
 			MaxIdleConns:          20000,
 			MaxIdleConnsPerHost:   1000, // see https://github.com/golang/go/issues/13801
 			DisableKeepAlives:     !opts.keepAlivesEnabled,
@@ -914,8 +914,8 @@ func (rt *oauth2RoundTripper) newOauth2TokenSource(req *http.Request, secret str
 	tlsTransport := func(tlsConfig *tls.Config) (http.RoundTripper, error) {
 		return &http.Transport{
 			TLSClientConfig:       tlsConfig,
-			Proxy:                 rt.config.ProxyConfig.Proxy(),
-			ProxyConnectHeader:    rt.config.ProxyConfig.GetProxyConnectHeader(),
+			Proxy:                 rt.config.Proxy(),
+			ProxyConnectHeader:    rt.config.GetProxyConnectHeader(),
 			DisableKeepAlives:     !rt.opts.keepAlivesEnabled,
 			MaxIdleConns:          20,
 			MaxIdleConnsPerHost:   1, // see https://github.com/golang/go/issues/13801
@@ -1508,7 +1508,7 @@ func (c *ProxyConfig) Proxy() (fn func(*http.Request) (*url.URL, error)) {
 		}
 		return
 	}
-	if c.ProxyURL.URL != nil && c.ProxyURL.URL.String() != "" {
+	if c.ProxyURL.URL != nil && c.ProxyURL.String() != "" {
 		if c.NoProxy == "" {
 			c.proxyFunc = http.ProxyURL(c.ProxyURL.URL)
 			return
diff --git a/vendor/github.com/prometheus/common/expfmt/text_parse.go b/vendor/github.com/prometheus/common/expfmt/text_parse.go
index b4607fe4d27..4067978a178 100644
--- a/vendor/github.com/prometheus/common/expfmt/text_parse.go
+++ b/vendor/github.com/prometheus/common/expfmt/text_parse.go
@@ -345,8 +345,8 @@ func (p *TextParser) startLabelName() stateFn {
 	}
 	// Special summary/histogram treatment. Don't add 'quantile' and 'le'
 	// labels to 'real' labels.
-	if !(p.currentMF.GetType() == dto.MetricType_SUMMARY && p.currentLabelPair.GetName() == model.QuantileLabel) &&
-		!(p.currentMF.GetType() == dto.MetricType_HISTOGRAM && p.currentLabelPair.GetName() == model.BucketLabel) {
+	if (p.currentMF.GetType() != dto.MetricType_SUMMARY || p.currentLabelPair.GetName() != model.QuantileLabel) &&
+		(p.currentMF.GetType() != dto.MetricType_HISTOGRAM || p.currentLabelPair.GetName() != model.BucketLabel) {
 		p.currentLabelPairs = append(p.currentLabelPairs, p.currentLabelPair)
 	}
 	// Check for duplicate label names.
diff --git a/vendor/github.com/prometheus/common/model/labels.go b/vendor/github.com/prometheus/common/model/labels.go
index f4a387605f1..de83afe93e9 100644
--- a/vendor/github.com/prometheus/common/model/labels.go
+++ b/vendor/github.com/prometheus/common/model/labels.go
@@ -122,7 +122,8 @@ func (ln LabelName) IsValidLegacy() bool {
 		return false
 	}
 	for i, b := range ln {
-		if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || (b >= '0' && b <= '9' && i > 0)) {
+		// TODO: Apply De Morgan's law. Make sure there are tests for this.
+		if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || (b >= '0' && b <= '9' && i > 0)) { //nolint:staticcheck
 			return false
 		}
 	}
diff --git a/vendor/github.com/prometheus/common/model/time.go b/vendor/github.com/prometheus/common/model/time.go
index 5727452c1ee..fed9e87b915 100644
--- a/vendor/github.com/prometheus/common/model/time.go
+++ b/vendor/github.com/prometheus/common/model/time.go
@@ -201,6 +201,7 @@ var unitMap = map[string]struct {
 
 // ParseDuration parses a string into a time.Duration, assuming that a year
 // always has 365d, a week always has 7d, and a day always has 24h.
+// Negative durations are not supported.
 func ParseDuration(s string) (Duration, error) {
 	switch s {
 	case "0":
@@ -253,18 +254,36 @@ func ParseDuration(s string) (Duration, error) {
 			return 0, errors.New("duration out of range")
 		}
 	}
+
 	return Duration(dur), nil
 }
 
+// ParseDurationAllowNegative is like ParseDuration but also accepts negative durations.
+func ParseDurationAllowNegative(s string) (Duration, error) {
+	if s == "" || s[0] != '-' {
+		return ParseDuration(s)
+	}
+
+	d, err := ParseDuration(s[1:])
+
+	return -d, err
+}
+
 func (d Duration) String() string {
 	var (
-		ms = int64(time.Duration(d) / time.Millisecond)
-		r  = ""
+		ms   = int64(time.Duration(d) / time.Millisecond)
+		r    = ""
+		sign = ""
 	)
+
 	if ms == 0 {
 		return "0s"
 	}
 
+	if ms < 0 {
+		sign, ms = "-", -ms
+	}
+
 	f := func(unit string, mult int64, exact bool) {
 		if exact && ms%mult != 0 {
 			return
@@ -286,7 +305,7 @@ func (d Duration) String() string {
 	f("s", 1000, false)
 	f("ms", 1, false)
 
-	return r
+	return sign + r
 }
 
 // MarshalJSON implements the json.Marshaler interface.
diff --git a/vendor/github.com/prometheus/common/promslog/slog.go b/vendor/github.com/prometheus/common/promslog/slog.go
index f9f89966315..8da43aef527 100644
--- a/vendor/github.com/prometheus/common/promslog/slog.go
+++ b/vendor/github.com/prometheus/common/promslog/slog.go
@@ -76,6 +76,11 @@ func (l *Level) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	return nil
 }
 
+// Level returns the value of the logging level as an slog.Level.
+func (l *Level) Level() slog.Level {
+	return l.lvl.Level()
+}
+
 // String returns the current level.
 func (l *Level) String() string {
 	switch l.lvl.Level() {
@@ -200,9 +205,8 @@ func defaultReplaceAttr(_ []string, a slog.Attr) slog.Attr {
 	key := a.Key
 	switch key {
 	case slog.TimeKey:
-		if t, ok := a.Value.Any().(time.Time); ok {
-			a.Value = slog.TimeValue(t.UTC())
-		} else {
+		// Note that we do not change the timezone to UTC anymore.
+		if _, ok := a.Value.Any().(time.Time); !ok {
 			// If we can't cast the any from the value to a
 			// time.Time, it means the caller logged
 			// another attribute with a key of `time`.
@@ -267,5 +271,5 @@ func New(config *Config) *slog.Logger {
 // NewNopLogger is a convenience function to return an slog.Logger that writes
 // to io.Discard.
 func NewNopLogger() *slog.Logger {
-	return slog.New(slog.NewTextHandler(io.Discard, nil))
+	return New(&Config{Writer: io.Discard})
 }
diff --git a/vendor/modules.txt b/vendor/modules.txt
index ca8316be582..142d5c5662a 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -1035,8 +1035,8 @@ github.com/prometheus/client_golang/prometheus/testutil/promlint/validations
 # github.com/prometheus/client_model v0.6.2
 ## explicit; go 1.22.0
 github.com/prometheus/client_model/go
-# github.com/prometheus/common v0.63.0
-## explicit; go 1.21
+# github.com/prometheus/common v0.65.0
+## explicit; go 1.23.0
 github.com/prometheus/common/config
 github.com/prometheus/common/expfmt
 github.com/prometheus/common/helpers/templates
@@ -1052,7 +1052,7 @@ github.com/prometheus/exporter-toolkit/web
 github.com/prometheus/procfs
 github.com/prometheus/procfs/internal/fs
 github.com/prometheus/procfs/internal/util
-# github.com/prometheus/prometheus v0.303.1 => github.com/thanos-io/thanos-prometheus v0.0.0-20250610133519-082594458a88
+# github.com/prometheus/prometheus v1.99.0 => github.com/thanos-io/thanos-prometheus v0.0.0-20250610133519-082594458a88
 ## explicit; go 1.23.0
 github.com/prometheus/prometheus/config
 github.com/prometheus/prometheus/discovery