diff --git a/go.mod b/go.mod
index a53e86b369c..e167aad9b2f 100644
--- a/go.mod
+++ b/go.mod
@@ -15,7 +15,7 @@ require (
 	github.com/moby/sys/userns v0.1.0
 	github.com/mrunalp/fileutils v0.5.1
 	github.com/opencontainers/cgroups v0.0.5
-	github.com/opencontainers/runtime-spec v1.2.2-0.20250818071321-383cadbf08c0
+	github.com/opencontainers/runtime-spec v1.2.2-0.20251022072015-5caf3047c341
 	github.com/opencontainers/selinux v1.12.0
 	github.com/seccomp/libseccomp-golang v0.11.1
 	github.com/sirupsen/logrus v1.9.3
@@ -32,3 +32,5 @@ require (
 	github.com/cpuguy83/go-md2man/v2 v2.0.7 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
 )
+
+replace github.com/opencontainers/cgroups v0.0.5 => github.com/cyphar/oci-cgroups v0.0.0-20251025144234-7c34f099ee0b
diff --git a/go.sum b/go.sum
index 45bc4513954..f419bf9bf0e 100644
--- a/go.sum
+++ b/go.sum
@@ -11,6 +11,8 @@ github.com/cpuguy83/go-md2man/v2 v2.0.7 h1:zbFlGlXEAKlwXpmvle3d8Oe3YnkKIK4xSRTd3
 github.com/cpuguy83/go-md2man/v2 v2.0.7/go.mod h1:oOW0eioCTA6cOiMLiUPZOpcVxMig6NIQQ7OS05n1F4g=
 github.com/cyphar/filepath-securejoin v0.4.1 h1:JyxxyPEaktOD+GAnqIqTf9A8tHyAG22rowi7HkoSU1s=
 github.com/cyphar/filepath-securejoin v0.4.1/go.mod h1:Sdj7gXlvMcPZsbhwhQ33GguGLDGQL7h7bg04C/+u9jI=
+github.com/cyphar/oci-cgroups v0.0.0-20251025144234-7c34f099ee0b h1:xzotBueLMeuibA0KuEOJ5X1qTNfpWFwWCDszJoXO+SI=
+github.com/cyphar/oci-cgroups v0.0.0-20251025144234-7c34f099ee0b/go.mod h1:oWVzJsKK0gG9SCRBfTpnn16WcGEqDI8PAcpMGbqWxcs=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -44,10 +46,8 @@ github.com/moby/sys/userns v0.1.0 h1:tVLXkFOxVu9A64/yh59slHVv9ahO9UIev4JZusOLG/g
 github.com/moby/sys/userns v0.1.0/go.mod h1:IHUYgu/kao6N8YZlp9Cf444ySSvCmDlmzUcYfDHOl28=
 github.com/mrunalp/fileutils v0.5.1 h1:F+S7ZlNKnrwHfSwdlgNSkKo67ReVf8o9fel6C3dkm/Q=
 github.com/mrunalp/fileutils v0.5.1/go.mod h1:M1WthSahJixYnrXQl/DFQuteStB1weuxD2QJNHXfbSQ=
-github.com/opencontainers/cgroups v0.0.5 h1:DRITAqcOnY0uSBzIpt1RYWLjh5DPDiqUs4fY6Y0ktls=
-github.com/opencontainers/cgroups v0.0.5/go.mod h1:oWVzJsKK0gG9SCRBfTpnn16WcGEqDI8PAcpMGbqWxcs=
-github.com/opencontainers/runtime-spec v1.2.2-0.20250818071321-383cadbf08c0 h1:RLn0YfUWkiqPGtgUANvJrcjIkCHGRl3jcz/c557M28M=
-github.com/opencontainers/runtime-spec v1.2.2-0.20250818071321-383cadbf08c0/go.mod h1:jwyrGlmzljRJv/Fgzds9SsS/C5hL+LL3ko9hs6T5lQ0=
+github.com/opencontainers/runtime-spec v1.2.2-0.20251022072015-5caf3047c341 h1:fQ6LUhSWtHE2SdjVfrgANsFgQZtCNDTjUhussoMtX+8=
+github.com/opencontainers/runtime-spec v1.2.2-0.20251022072015-5caf3047c341/go.mod h1:jwyrGlmzljRJv/Fgzds9SsS/C5hL+LL3ko9hs6T5lQ0=
 github.com/opencontainers/selinux v1.12.0 h1:6n5JV4Cf+4y0KNXW48TLj5DwfXpvWlxXplUkdTrmPb8=
 github.com/opencontainers/selinux v1.12.0/go.mod h1:BTPX+bjVbWGXw7ZZWUbdENt8w0htPSrlgOOysQaU62U=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
diff --git a/libcontainer/integration/exec_test.go b/libcontainer/integration/exec_test.go
index f5a24777edf..e3362842031 100644
--- a/libcontainer/integration/exec_test.go
+++ b/libcontainer/integration/exec_test.go
@@ -525,20 +525,22 @@ func TestPidsSystemd(t *testing.T) {
 	testPids(t, true)
 }
 
+func mkPtr[T any](v T) *T { return &v }
+
 func testPids(t *testing.T, systemd bool) {
 	if testing.Short() {
 		return
 	}
 
 	config := newTemplateConfig(t, &tParam{systemd: systemd})
-	config.Cgroups.Resources.PidsLimit = -1
+	config.Cgroups.Resources.PidsLimit = mkPtr[int64](-1)
 
 	// Running multiple processes, expecting it to succeed with no pids limit.
 	runContainerOk(t, config, "/bin/sh", "-c", "/bin/true | /bin/true | /bin/true | /bin/true")
 
 	// Enforce a permissive limit. This needs to be fairly hand-wavey due to the
 	// issues with running Go binaries with pids restrictions (see below).
-	config.Cgroups.Resources.PidsLimit = 64
+	config.Cgroups.Resources.PidsLimit = mkPtr[int64](64)
 	runContainerOk(t, config, "/bin/sh", "-c", `
 	/bin/true | /bin/true | /bin/true | /bin/true | /bin/true | /bin/true | bin/true | /bin/true |
 	/bin/true | /bin/true | /bin/true | /bin/true | /bin/true | /bin/true | bin/true | /bin/true |
@@ -547,7 +549,7 @@ func testPids(t *testing.T, systemd bool) {
 
 	// Enforce a restrictive limit. 64 * /bin/true + 1 * shell should cause
 	// this to fail reliably.
-	config.Cgroups.Resources.PidsLimit = 64
+	config.Cgroups.Resources.PidsLimit = mkPtr[int64](64)
 	out, _, err := runContainer(t, config, "/bin/sh", "-c", `
 	/bin/true | /bin/true | /bin/true | /bin/true | /bin/true | /bin/true | bin/true | /bin/true |
 	/bin/true | /bin/true | /bin/true | /bin/true | /bin/true | /bin/true | bin/true | /bin/true |
diff --git a/man/runc-update.8.md b/man/runc-update.8.md
index 0e95d85ded1..af23be35ca8 100644
--- a/man/runc-update.8.md
+++ b/man/runc-update.8.md
@@ -85,7 +85,8 @@ stdin. If this option is used, all other options are ignored.
 (i.e. use unlimited swap).
 
 **--pids-limit** _num_
-: Set the maximum number of processes allowed in the container.
+: Set the maximum number of processes allowed in the container. Use **-1** to
+unset the limit.
 
 **--l3-cache-schema** _value_
 : Set the value for Intel RDT/CAT L3 cache schema.
diff --git a/tests/integration/cgroups.bats b/tests/integration/cgroups.bats
index a2df63e8002..42d20dec8d5 100644
--- a/tests/integration/cgroups.bats
+++ b/tests/integration/cgroups.bats
@@ -324,6 +324,36 @@ convert_hugetlb_size() {
 	done
 }
 
+# https://github.com/opencontainers/runc/issues/4014.
+@test "runc run (pids.limit=0 is 0)" {
+	[ $EUID -ne 0 ] && requires rootless_cgroup
+	requires cgroups_pids
+
+	set_cgroups_path
+	update_config '.linux.resources.pids.limit = 0'
+
+	runc run -d --console-socket "$CONSOLE_SOCKET" test_pids
+	[ "$status" -eq 0 ]
+	# systemd doesn't support TasksMax=0 so runc will silently remap it to 1.
+	check_cgroup_value "pids.max" "1"
+	check_systemd_value "TasksMax" "1"
+}
+
+# https://github.com/opencontainers/runc/issues/4014.
+@test "runc run (pids.limit=-1 means unlimited)" {
+	[ $EUID -ne 0 ] && requires rootless_cgroup
+	requires cgroups_pids
+
+	set_cgroups_path
+	update_config '.linux.resources.pids.limit = -1'
+
+	runc run -d --console-socket "$CONSOLE_SOCKET" test_pids
+	[ "$status" -eq 0 ]
+	check_cgroup_value "pids.max" "max"
+	# systemd < v227 shows UINT64_MAX instead of "infinity".
+	check_systemd_value "TasksMax" "infinity" "18446744073709551615"
+}
+
 @test "runc run (cgroup v2 resources.unified only)" {
 	requires root cgroups_v2
 
@@ -390,6 +420,7 @@ convert_hugetlb_size() {
 	set_cgroups_path
 	# CPU shares of 3333 corresponds to CPU weight of 128.
 	update_config '   .linux.resources.memory |= {"limit": 33554432}
+			| .linux.resources.pids.limit = 100
 			| .linux.resources.cpu |= {
 				"shares": 3333,
 				"quota": 40000,
diff --git a/tests/integration/update.bats b/tests/integration/update.bats
index 29d36fdfa2a..07f3eff1733 100644
--- a/tests/integration/update.bats
+++ b/tests/integration/update.bats
@@ -327,6 +327,37 @@ EOF
 	check_cpu_shares 100
 }
 
+@test "update pids.limit" {
+	[ $EUID -ne 0 ] && requires rootless_cgroup
+	requires cgroups_pids
+
+	runc run -d --console-socket "$CONSOLE_SOCKET" test_update
+	[ "$status" -eq 0 ]
+
+	check_cgroup_value "pids.max" 20
+	check_systemd_value "TasksMax" 20
+
+	runc update test_update --pids-limit 12345
+	[ "$status" -eq 0 ]
+
+	check_cgroup_value "pids.max" "12345"
+	check_systemd_value "TasksMax" "12345"
+
+	runc update test_update --pids-limit -1
+	[ "$status" -eq 0 ]
+
+	check_cgroup_value "pids.max" "max"
+	# systemd < v227 shows UINT64_MAX instead of "infinity".
+	check_systemd_value "TasksMax" "infinity" "18446744073709551615"
+
+	runc update test_update --pids-limit 0
+	[ "$status" -eq 0 ]
+
+	# systemd doesn't support TasksMax=0 so runc will silently remap it to 1.
+	check_cgroup_value "pids.max" "1"
+	check_systemd_value "TasksMax" "1"
+}
+
 @test "cpu burst" {
 	[ $EUID -ne 0 ] && requires rootless_cgroup
 	requires cgroups_cpu_burst
diff --git a/update.go b/update.go
index 8510c217cd5..e4abb1ef552 100644
--- a/update.go
+++ b/update.go
@@ -252,7 +252,9 @@ other options are ignored.
 				}
 			}
 
-			r.Pids.Limit = int64(context.Int("pids-limit"))
+			if context.IsSet("pids-limit") {
+				r.Pids.Limit = i64Ptr(int64(context.Int("pids-limit")))
+			}
 		}
 
 		// Fix up values
diff --git a/vendor/github.com/opencontainers/cgroups/config_linux.go b/vendor/github.com/opencontainers/cgroups/config_linux.go
index 9bc58a3789b..3d29d938bf0 100644
--- a/vendor/github.com/opencontainers/cgroups/config_linux.go
+++ b/vendor/github.com/opencontainers/cgroups/config_linux.go
@@ -90,8 +90,8 @@ type Resources struct {
 	// Cgroup's SCHED_IDLE value.
 	CPUIdle *int64 `json:"cpu_idle,omitempty"`
 
-	// Process limit; set <= `0' to disable limit.
-	PidsLimit int64 `json:"pids_limit,omitempty"`
+	// Process limit; set < `0' to disable limit. `nil` means "keep current limit".
+	PidsLimit *int64 `json:"pids_limit,omitempty"`
 
 	// Specifies per cgroup weight, range is from 10 to 1000.
 	BlkioWeight uint16 `json:"blkio_weight,omitempty"`
diff --git a/vendor/github.com/opencontainers/cgroups/fs/pids.go b/vendor/github.com/opencontainers/cgroups/fs/pids.go
index 9319761e6ad..36bd339af82 100644
--- a/vendor/github.com/opencontainers/cgroups/fs/pids.go
+++ b/vendor/github.com/opencontainers/cgroups/fs/pids.go
@@ -19,19 +19,24 @@ func (s *PidsGroup) Apply(path string, _ *cgroups.Resources, pid int) error {
 }
 
 func (s *PidsGroup) Set(path string, r *cgroups.Resources) error {
-	if r.PidsLimit != 0 {
-		// "max" is the fallback value.
-		limit := "max"
-
-		if r.PidsLimit > 0 {
-			limit = strconv.FormatInt(r.PidsLimit, 10)
-		}
-
-		if err := cgroups.WriteFile(path, "pids.max", limit); err != nil {
-			return err
-		}
+	if r.PidsLimit == nil {
+		return nil
 	}
 
+	// "max" is the fallback value.
+	val := "max"
+	if limit := *r.PidsLimit; limit > 0 {
+		val = strconv.FormatInt(limit, 10)
+	} else if limit == 0 {
+		// systemd doesn't support setting pids.max to "0", so when setting
+		// TasksMax we need to remap it to "1". We do the same thing here to
+		// avoid flip-flop behaviour between the fs and systemd drivers. In
+		// practice, the pids cgroup behaviour is basically identical.
+		val = "1"
+	}
+	if err := cgroups.WriteFile(path, "pids.max", val); err != nil {
+		return err
+	}
 	return nil
 }
 
diff --git a/vendor/github.com/opencontainers/cgroups/fs2/pids.go b/vendor/github.com/opencontainers/cgroups/fs2/pids.go
index 9b82b90115e..f932259ad56 100644
--- a/vendor/github.com/opencontainers/cgroups/fs2/pids.go
+++ b/vendor/github.com/opencontainers/cgroups/fs2/pids.go
@@ -4,6 +4,7 @@ import (
 	"errors"
 	"math"
 	"os"
+	"strconv"
 	"strings"
 
 	"golang.org/x/sys/unix"
@@ -13,19 +14,26 @@ import (
 )
 
 func isPidsSet(r *cgroups.Resources) bool {
-	return r.PidsLimit != 0
+	return r.PidsLimit != nil
 }
 
 func setPids(dirPath string, r *cgroups.Resources) error {
 	if !isPidsSet(r) {
 		return nil
 	}
-	if val := numToStr(r.PidsLimit); val != "" {
-		if err := cgroups.WriteFile(dirPath, "pids.max", val); err != nil {
-			return err
-		}
+	val := "max"
+	if limit := *r.PidsLimit; limit > 0 {
+		val = strconv.FormatInt(limit, 10)
+	} else if limit == 0 {
+		// systemd doesn't support setting pids.max to "0", so when setting
+		// TasksMax we need to remap it to "1". We do the same thing here to
+		// avoid flip-flop behaviour between the fs and systemd drivers. In
+		// practice, the pids cgroup behaviour is basically identical.
+		val = "1"
+	}
+	if err := cgroups.WriteFile(dirPath, "pids.max", val); err != nil {
+		return err
 	}
-
 	return nil
 }
 
diff --git a/vendor/github.com/opencontainers/cgroups/systemd/v1.go b/vendor/github.com/opencontainers/cgroups/systemd/v1.go
index 5500a53ac0f..96e69bb8608 100644
--- a/vendor/github.com/opencontainers/cgroups/systemd/v1.go
+++ b/vendor/github.com/opencontainers/cgroups/systemd/v1.go
@@ -2,6 +2,7 @@ package systemd
 
 import (
 	"errors"
+	"math"
 	"os"
 	"path/filepath"
 	"strings"
@@ -97,9 +98,17 @@ func genV1ResourcesProperties(r *cgroups.Resources, cm *dbusConnManager) ([]syst
 			newProp("BlockIOWeight", uint64(r.BlkioWeight)))
 	}
 
-	if r.PidsLimit > 0 || r.PidsLimit == -1 {
+	if r.PidsLimit != nil {
+		var tasksMax uint64
+		if limit := *r.PidsLimit; limit < 0 {
+			tasksMax = math.MaxUint64 // "infinity"
+		} else if limit == 0 {
+			tasksMax = 1 // systemd does not accept "0" for TasksMax
+		} else {
+			tasksMax = uint64(limit)
+		}
 		properties = append(properties,
-			newProp("TasksMax", uint64(r.PidsLimit)))
+			newProp("TasksMax", tasksMax))
 	}
 
 	err = addCpuset(cm, &properties, r.CpusetCpus, r.CpusetMems)
diff --git a/vendor/github.com/opencontainers/cgroups/systemd/v2.go b/vendor/github.com/opencontainers/cgroups/systemd/v2.go
index c2f2e87f3ba..f76c93e8444 100644
--- a/vendor/github.com/opencontainers/cgroups/systemd/v2.go
+++ b/vendor/github.com/opencontainers/cgroups/systemd/v2.go
@@ -176,6 +176,9 @@ func unifiedResToSystemdProps(cm *dbusConnManager, res map[string]string) (props
 					return nil, fmt.Errorf("unified resource %q value conversion error: %w", k, err)
 				}
 			}
+			if num == 0 {
+				num = 1 // systemd does not accept "0" for TasksMax
+			}
 			props = append(props,
 				newProp("TasksMax", num))
 
@@ -256,9 +259,17 @@ func genV2ResourcesProperties(dirPath string, r *cgroups.Resources, cm *dbusConn
 
 	addCPUQuota(cm, &properties, &r.CpuQuota, r.CpuPeriod)
 
-	if r.PidsLimit > 0 || r.PidsLimit == -1 {
+	if r.PidsLimit != nil {
+		var tasksMax uint64
+		if limit := *r.PidsLimit; limit < 0 {
+			tasksMax = math.MaxUint64 // "infinity"
+		} else if limit == 0 {
+			tasksMax = 1 // systemd does not accept "0" for TasksMax
+		} else {
+			tasksMax = uint64(limit)
+		}
 		properties = append(properties,
-			newProp("TasksMax", uint64(r.PidsLimit)))
+			newProp("TasksMax", tasksMax))
 	}
 
 	err = addCpuset(cm, &properties, r.CpusetCpus, r.CpusetMems)
diff --git a/vendor/github.com/opencontainers/runtime-spec/specs-go/config.go b/vendor/github.com/opencontainers/runtime-spec/specs-go/config.go
index 36d28032e66..bce831f6f90 100644
--- a/vendor/github.com/opencontainers/runtime-spec/specs-go/config.go
+++ b/vendor/github.com/opencontainers/runtime-spec/specs-go/config.go
@@ -434,7 +434,7 @@ type LinuxCPU struct {
 // LinuxPids for Linux cgroup 'pids' resource management (Linux 4.3)
 type LinuxPids struct {
 	// Maximum number of PIDs. Default is "no limit".
-	Limit int64 `json:"limit"`
+	Limit *int64 `json:"limit,omitempty"`
 }
 
 // LinuxNetwork identification and priority configuration
@@ -688,6 +688,32 @@ type WindowsHyperV struct {
 	UtilityVMPath string `json:"utilityVMPath,omitempty"`
 }
 
+// IOMems contains information about iomem addresses that should be passed to the VM.
+type IOMems struct {
+	// Guest Frame Number to map the iomem range. If GFN is not specified, the mapping will be done to the same Frame Number as was provided in FirstMFN.
+	FirstGFN *uint64 `json:"firstGFN,omitempty"`
+	// Physical page number of iomem regions.
+	FirstMFN *uint64 `json:"firstMFN"`
+	// Number of pages to be mapped.
+	NrMFNs *uint64 `json:"nrMFNs"`
+}
+
+// Hardware configuration for the VM image
+type HWConfig struct {
+	// Path to the container device-tree file that should be passed to the VM configuration.
+	DeviceTree string `json:"deviceTree,omitempty"`
+	// Number of virtual cpus for the VM.
+	VCPUs *uint32 `json:"vcpus,omitempty"`
+	// Maximum memory in bytes allocated to the VM.
+	Memory *uint64 `json:"memory,omitempty"`
+	// Host device tree nodes to passthrough to the VM.
+	DtDevs []string `json:"dtdevs,omitempty"`
+	// Allow auto-translated domains to access specific hardware I/O memory pages.
+	IOMems []IOMems `json:"iomems,omitempty"`
+	// Allows VM to access specific physical IRQs.
+	Irqs []uint32 `json:"irqs,omitempty"`
+}
+
 // VM contains information for virtual-machine-based containers.
 type VM struct {
 	// Hypervisor specifies hypervisor-related configuration for virtual-machine-based containers.
@@ -696,6 +722,8 @@ type VM struct {
 	Kernel VMKernel `json:"kernel"`
 	// Image specifies guest image related configuration for virtual-machine-based containers.
 	Image VMImage `json:"image,omitempty"`
+	// Hardware configuration that should be passed to the VM.
+	HwConfig *HWConfig `json:"hwconfig,omitempty"`
 }
 
 // VMHypervisor contains information about the hypervisor to use for a virtual machine.
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 3633df7018e..b82fba17212 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -51,7 +51,7 @@ github.com/moby/sys/userns
 # github.com/mrunalp/fileutils v0.5.1
 ## explicit; go 1.13
 github.com/mrunalp/fileutils
-# github.com/opencontainers/cgroups v0.0.5
+# github.com/opencontainers/cgroups v0.0.5 => github.com/cyphar/oci-cgroups v0.0.0-20251025144234-7c34f099ee0b
 ## explicit; go 1.23.0
 github.com/opencontainers/cgroups
 github.com/opencontainers/cgroups/devices
@@ -62,7 +62,7 @@ github.com/opencontainers/cgroups/fscommon
 github.com/opencontainers/cgroups/internal/path
 github.com/opencontainers/cgroups/manager
 github.com/opencontainers/cgroups/systemd
-# github.com/opencontainers/runtime-spec v1.2.2-0.20250818071321-383cadbf08c0
+# github.com/opencontainers/runtime-spec v1.2.2-0.20251022072015-5caf3047c341
 ## explicit
 github.com/opencontainers/runtime-spec/specs-go
 github.com/opencontainers/runtime-spec/specs-go/features