diff --git a/docs/src/pages/migrations.md b/docs/src/pages/migrations.md
index 6efe74623..229428f75 100644
--- a/docs/src/pages/migrations.md
+++ b/docs/src/pages/migrations.md
@@ -17,6 +17,7 @@ This will be the next version of Woodpecker.
   - `CI_PIPELINE_FINISHED` as empty during execution
   - `CI_PIPELINE_STATUS` was always `success`
   - `CI_STEP_STATUS` was always `success`
+- `CI_COMMIT_BRANCH` now always returns the source branch, even for pull requests (previously it returned the target branch)
 - Set `/woodpecker` as default workdir for the **woodpecker-cli** container
 - Secret filters for plugins now check against tag if specified
 - Compatibility mode of deprecated `pipeline:`, `platform:` and `branches:` pipeline config options are now removed and pipeline will now fail if still in use.
diff --git a/pipeline/frontend/metadata/environment.go b/pipeline/frontend/metadata/environment.go
index 2d406820e..ebb64543c 100644
--- a/pipeline/frontend/metadata/environment.go
+++ b/pipeline/frontend/metadata/environment.go
@@ -87,11 +87,12 @@ func (m *Metadata) Environ() map[string]string {
 	// CI_STEP_STARTED will be set by agent
 
 	commit := pipeline.Commit
+	sourceBranch, targetBranch := getSourceTargetBranches(commit.Refspec)
 	setNonEmptyEnvVar(params, "CI_COMMIT_SHA", commit.Sha)
 	setNonEmptyEnvVar(params, "CI_COMMIT_REF", commit.Ref)
 	setNonEmptyEnvVar(params, "CI_COMMIT_REFSPEC", commit.Refspec)
 	setNonEmptyEnvVar(params, "CI_COMMIT_MESSAGE", commit.Message)
-	setNonEmptyEnvVar(params, "CI_COMMIT_BRANCH", commit.Branch)
+	setNonEmptyEnvVar(params, "CI_COMMIT_BRANCH", sourceBranch)
 	setNonEmptyEnvVar(params, "CI_COMMIT_AUTHOR", commit.Author.Name)
 	setNonEmptyEnvVar(params, "CI_COMMIT_AUTHOR_EMAIL", commit.Author.Email)
 	setNonEmptyEnvVar(params, "CI_COMMIT_AUTHOR_AVATAR", commit.Author.Avatar)
@@ -102,7 +103,6 @@ func (m *Metadata) Environ() map[string]string {
 		setNonEmptyEnvVar(params, "CI_COMMIT_PRERELEASE", strconv.FormatBool(pipeline.Commit.IsPrerelease))
 	}
 	if pipeline.Event == EventPull || pipeline.Event == EventPullClosed {
-		sourceBranch, targetBranch := getSourceTargetBranches(commit.Refspec)
 		setNonEmptyEnvVar(params, "CI_COMMIT_SOURCE_BRANCH", sourceBranch)
 		setNonEmptyEnvVar(params, "CI_COMMIT_TARGET_BRANCH", targetBranch)
 		setNonEmptyEnvVar(params, "CI_COMMIT_PULL_REQUEST", pullRegexp.FindString(pipeline.Commit.Ref))
@@ -137,16 +137,16 @@ func (m *Metadata) Environ() map[string]string {
 	setNonEmptyEnvVar(params, "CI_PREV_PIPELINE_FINISHED", strconv.FormatInt(prevPipeline.Finished, 10))
 
 	prevCommit := prevPipeline.Commit
+	prevSourceBranch, prevTargetBranch := getSourceTargetBranches(prevCommit.Refspec)
 	setNonEmptyEnvVar(params, "CI_PREV_COMMIT_SHA", prevCommit.Sha)
 	setNonEmptyEnvVar(params, "CI_PREV_COMMIT_REF", prevCommit.Ref)
 	setNonEmptyEnvVar(params, "CI_PREV_COMMIT_REFSPEC", prevCommit.Refspec)
 	setNonEmptyEnvVar(params, "CI_PREV_COMMIT_MESSAGE", prevCommit.Message)
-	setNonEmptyEnvVar(params, "CI_PREV_COMMIT_BRANCH", prevCommit.Branch)
+	setNonEmptyEnvVar(params, "CI_PREV_COMMIT_BRANCH", prevSourceBranch)
 	setNonEmptyEnvVar(params, "CI_PREV_COMMIT_AUTHOR", prevCommit.Author.Name)
 	setNonEmptyEnvVar(params, "CI_PREV_COMMIT_AUTHOR_EMAIL", prevCommit.Author.Email)
 	setNonEmptyEnvVar(params, "CI_PREV_COMMIT_AUTHOR_AVATAR", prevCommit.Author.Avatar)
 	if prevPipeline.Event == EventPull || prevPipeline.Event == EventPullClosed {
-		prevSourceBranch, prevTargetBranch := getSourceTargetBranches(prevCommit.Refspec)
 		setNonEmptyEnvVar(params, "CI_PREV_COMMIT_SOURCE_BRANCH", prevSourceBranch)
 		setNonEmptyEnvVar(params, "CI_PREV_COMMIT_TARGET_BRANCH", prevTargetBranch)
 	}