diff --git a/cmd/hook.go b/cmd/hook.go
index 11d0d072c9..b1ece0ede9 100644
--- a/cmd/hook.go
+++ b/cmd/hook.go
@@ -197,6 +197,7 @@ Gitea or set your environment appropriately.`, "")
 		PullRequestID:                   prID,
 		DeployKeyID:                     deployKeyID,
 		ActionPerm:                      int(actionPerm),
+		PushTrigger:                     repo_module.PushTrigger(os.Getenv(repo_module.EnvPushTrigger)),
 	}
 
 	scanner := bufio.NewScanner(os.Stdin)
diff --git a/models/pull/automerge.go b/models/pull/automerge.go
index f69fcb60d1..f31159a8d8 100644
--- a/models/pull/automerge.go
+++ b/models/pull/automerge.go
@@ -74,7 +74,7 @@ func GetScheduledMergeByPullID(ctx context.Context, pullID int64) (bool, *AutoMe
 		return false, nil, err
 	}
 
-	doer, err := user_model.GetUserByID(ctx, scheduledPRM.DoerID)
+	doer, err := user_model.GetPossibleUserByID(ctx, scheduledPRM.DoerID)
 	if err != nil {
 		return false, nil, err
 	}
diff --git a/routers/private/hook_post_receive.go b/routers/private/hook_post_receive.go
index 5c01216356..9b8430d6c1 100644
--- a/routers/private/hook_post_receive.go
+++ b/routers/private/hook_post_receive.go
@@ -332,7 +332,7 @@ func HookPostReceive(ctx *gitea_context.PrivateContext) {
 
 func loadContextCacheUser(ctx context.Context, id int64) (*user_model.User, error) {
 	return cache.GetWithContextCache(ctx, "hook_post_receive_user", id, func() (*user_model.User, error) {
-		return user_model.GetUserByID(ctx, id)
+		return user_model.GetPossibleUserByID(ctx, id)
 	})
 }
 
diff --git a/services/automerge/automerge.go b/services/automerge/automerge.go
index a1ee204882..361eae9e47 100644
--- a/services/automerge/automerge.go
+++ b/services/automerge/automerge.go
@@ -5,14 +5,12 @@ package automerge
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"strconv"
 	"strings"
 
 	"code.gitea.io/gitea/models/db"
 	issues_model "code.gitea.io/gitea/models/issues"
-	access_model "code.gitea.io/gitea/models/perm/access"
 	pull_model "code.gitea.io/gitea/models/pull"
 	repo_model "code.gitea.io/gitea/models/repo"
 	user_model "code.gitea.io/gitea/models/user"
@@ -275,26 +273,15 @@ func handlePullRequestAutoMerge(pullID int64, sha string) {
 	}
 
 	// Merge if all checks succeeded
-	doer, err := user_model.GetUserByID(ctx, scheduledPRM.DoerID)
+	// Use GetPossibleUserByID to allow merging by deleted users or bot users
+	doer, err := user_model.GetPossibleUserByID(ctx, scheduledPRM.DoerID)
 	if err != nil {
 		log.Error("Unable to get scheduled User[%d]: %v", scheduledPRM.DoerID, err)
 		return
 	}
 
-	perm, err := access_model.GetUserRepoPermission(ctx, pr.HeadRepo, doer)
-	if err != nil {
-		log.Error("GetUserRepoPermission %-v: %v", pr.HeadRepo, err)
-		return
-	}
-
-	if err := pull_service.CheckPullMergeable(ctx, doer, &perm, pr, pull_service.MergeCheckTypeGeneral, false); err != nil {
-		if errors.Is(err, pull_service.ErrUserNotAllowedToMerge) {
-			log.Info("%-v was scheduled to automerge by an unauthorized user", pr)
-			return
-		}
-		log.Error("%-v CheckPullMergeable: %v", pr, err)
-		return
-	}
+	// We don't check doer's permission here because their permissions have been checked
+	// before ids were written to the auto_merge table
 
 	if err := pull_service.Merge(ctx, pr, doer, baseGitRepo, scheduledPRM.MergeStyle, "", scheduledPRM.Message, true); err != nil {
 		log.Error("pull_service.Merge: %v", err)
diff --git a/services/pull/merge.go b/services/pull/merge.go
index a3fbe4f627..03da80c905 100644
--- a/services/pull/merge.go
+++ b/services/pull/merge.go
@@ -17,6 +17,7 @@ import (
 	"code.gitea.io/gitea/models/db"
 	git_model "code.gitea.io/gitea/models/git"
 	issues_model "code.gitea.io/gitea/models/issues"
+	"code.gitea.io/gitea/models/perm"
 	access_model "code.gitea.io/gitea/models/perm/access"
 	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unit"
@@ -331,6 +332,9 @@ func doMergeAndPush(ctx context.Context, pr *issues_model.PullRequest, doer *use
 	)
 
 	mergeCtx.env = append(mergeCtx.env, repo_module.EnvPushTrigger+"="+string(pushTrigger))
+	if pushTrigger == repo_module.PushTriggerPRMergeToBase {
+		mergeCtx.env = append(mergeCtx.env, fmt.Sprintf("%s=%d", repo_module.EnvActionPerm, perm.AccessModeWrite))
+	}
 	pushCmd := git.NewCommand(ctx, "push", "origin").AddDynamicArguments(baseBranch + ":" + git.BranchPrefix + pr.BaseBranch)
 
 	// Push back to upstream.