diff --git a/hugolib/rss_test.go b/hugolib/rss_test.go
index 0c3c21b90..34c2be393 100644
--- a/hugolib/rss_test.go
+++ b/hugolib/rss_test.go
@@ -96,3 +96,51 @@ Figure:
 
 	b.AssertFileContent("public/index.xml", "img src="http://example.com/images/sunset.jpg")
 }
+
+// Issue 13332.
+func TestRSSCanonifyURLsSubDir(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+baseURL = 'https://example.org/subdir'
+disableKinds = ['section','sitemap','taxonomy','term']
+[markup.goldmark.renderHooks.image]
+enableDefault = true
+[markup.goldmark.renderHooks.link]
+enableDefault = true
+-- layouts/_default/_markup/render-image.html --
+{{- $u := urls.Parse .Destination -}}
+{{- $src := $u.String | relURL -}}
+<img srcset="{{ $src }}" src="{{ $src }} 2x">
+<img src="{{ $src }}">
+{{- /**/ -}}
+-- layouts/_default/home.html --
+{{ .Content }}|
+-- layouts/_default/single.html --
+{{ .Content }}|
+-- layouts/_default/rss.xml --
+{{ with site.GetPage "/s1/p2" }}
+  {{ .Content | transform.XMLEscape | safeHTML }}
+{{ end }}
+-- content/s1/p1.md --
+---
+title: p1
+---
+-- content/s1/p2/index.md --
+---
+title: p2
+---
+![alt](a.jpg)
+
+[p1](/s1/p1)
+-- content/s1/p2/a.jpg --
+`
+
+	b := Test(t, files)
+
+	b.AssertFileContent("public/index.xml", "https://example.org/subdir/s1/p1/")
+	b.AssertFileContent("public/index.xml",
+		"img src=&#34;https://example.org/subdir/a.jpg",
+		"img srcset=&#34;https://example.org/subdir/a.jpg&#34; src=&#34;https://example.org/subdir/a.jpg 2x")
+}
diff --git a/transform/urlreplacers/absurl.go b/transform/urlreplacers/absurl.go
index 029d94da2..17fe15327 100644
--- a/transform/urlreplacers/absurl.go
+++ b/transform/urlreplacers/absurl.go
@@ -13,7 +13,9 @@
 
 package urlreplacers
 
-import "github.com/gohugoio/hugo/transform"
+import (
+	"github.com/gohugoio/hugo/transform"
+)
 
 var ar = newAbsURLReplacer()
 
diff --git a/transform/urlreplacers/absurlreplacer.go b/transform/urlreplacers/absurlreplacer.go
index a875e6fa8..601fd9a1f 100644
--- a/transform/urlreplacers/absurlreplacer.go
+++ b/transform/urlreplacers/absurlreplacer.go
@@ -16,9 +16,11 @@ package urlreplacers
 import (
 	"bytes"
 	"io"
+	"net/url"
 	"unicode"
 	"unicode/utf8"
 
+	"github.com/gohugoio/hugo/common/paths"
 	"github.com/gohugoio/hugo/transform"
 )
 
@@ -31,6 +33,9 @@ type absurllexer struct {
 	// path may be set to a "." relative path
 	path []byte
 
+	// The root path, without leading slash.
+	root []byte
+
 	pos   int // input position
 	start int // item start position
 
@@ -119,6 +124,9 @@ func checkCandidateBase(l *absurllexer) {
 	}
 	l.pos += relURLPrefixLen
 	l.w.Write(l.path)
+	if len(l.root) > 0 && bytes.HasPrefix(l.content[l.pos:], l.root) {
+		l.pos += len(l.root)
+	}
 	l.start = l.pos
 }
 
@@ -174,7 +182,11 @@ func checkCandidateSrcset(l *absurllexer) {
 	for i, f := range fields {
 		if f[0] == '/' {
 			l.w.Write(l.path)
-			l.w.Write(f[1:])
+			n := 1
+			if len(l.root) > 0 && bytes.HasPrefix(f[n:], l.root) {
+				n += len(l.root)
+			}
+			l.w.Write(f[n:])
 
 		} else {
 			l.w.Write(f)
@@ -229,10 +241,15 @@ func (l *absurllexer) replace() {
 }
 
 func doReplace(path string, ct transform.FromTo, quotes [][]byte) {
+	var root string
+	if u, err := url.Parse(path); err == nil {
+		root = paths.TrimLeading(u.Path)
+	}
 	lexer := &absurllexer{
 		content: ct.From().Bytes(),
 		w:       ct.To(),
 		path:    []byte(path),
+		root:    []byte(root),
 		quotes:  quotes,
 	}