diff --git a/src/core/struct_tree.js b/src/core/struct_tree.js
index fa2d6e98c..083230c2b 100644
--- a/src/core/struct_tree.js
+++ b/src/core/struct_tree.js
@@ -13,7 +13,12 @@
  * limitations under the License.
  */
 
-import { AnnotationPrefix, stringToPDFString, warn } from "../shared/util.js";
+import {
+  AnnotationPrefix,
+  stringToPDFString,
+  stringToUTF8String,
+  warn,
+} from "../shared/util.js";
 import { Dict, isName, Name, Ref, RefSetCache } from "./primitives.js";
 import { lookupNormalRect, stringToAsciiOrUTF16BE } from "./core_utils.js";
 import { BaseStream } from "./base_stream.js";
@@ -610,7 +615,8 @@ class StructElementNode {
       if (!isName(fileStream.dict.get("Subtype"), "application/mathml+xml")) {
         continue;
       }
-      return fileStream.getString();
+      // The default encoding for xml files is UTF-8.
+      return stringToUTF8String(fileStream.getString());
     }
     const A = this.dict.get("A");
     if (A instanceof Dict) {
diff --git a/test/integration/accessibility_spec.mjs b/test/integration/accessibility_spec.mjs
index 5bb2c7915..94472ddc8 100644
--- a/test/integration/accessibility_spec.mjs
+++ b/test/integration/accessibility_spec.mjs
@@ -346,6 +346,46 @@ describe("accessibility", () => {
     });
   });
 
+  describe("MathML with some attributes in AF entry from LaTeX", () => {
+    let pages;
+
+    beforeEach(async () => {
+      pages = await loadAndWait("bug1997343.pdf", ".textLayer");
+    });
+
+    afterEach(async () => {
+      await closePages(pages);
+    });
+
+    it("must check that the MathML is correctly inserted", async () => {
+      await Promise.all(
+        pages.map(async ([browserName, page]) => {
+          const isSanitizerSupported = await page.evaluate(() => {
+            try {
+              // eslint-disable-next-line no-undef
+              return typeof Sanitizer !== "undefined";
+            } catch {
+              return false;
+            }
+          });
+          if (isSanitizerSupported) {
+            const mathML = await page.$eval(
+              "span.structTree span[aria-owns='p21R_mc64']",
+              el => el?.innerHTML ?? ""
+            );
+            expect(mathML)
+              .withContext(`In ${browserName}`)
+              .toEqual(
+                '<math display="block"> <msup> <mi>𝑛</mi> <mi>𝑝</mi> </msup> <mo lspace="0.278em" rspace="0.278em">=</mo> <mi>𝑛</mi> <mspace width="1.000em"></mspace> <mi> mod </mi> <mspace width="0.167em"></mspace> <mspace width="0.167em"></mspace> <mi>𝑝</mi> </math>'
+              );
+          } else {
+            pending(`Sanitizer API (in ${browserName}) is not supported`);
+          }
+        })
+      );
+    });
+  });
+
   describe("MathML tags in the struct tree", () => {
     let pages;
 
diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
index ed64906db..1eb2dce1b 100644
--- a/test/pdfs/.gitignore
+++ b/test/pdfs/.gitignore
@@ -753,3 +753,4 @@
 !bug1937438_af_from_latex.pdf
 !bug1937438_from_word.pdf
 !bug1937438_mml_from_latex.pdf
+!bug1997343.pdf
diff --git a/test/pdfs/bug1997343.pdf b/test/pdfs/bug1997343.pdf
new file mode 100755
index 000000000..378d0fc41
Binary files /dev/null and b/test/pdfs/bug1997343.pdf differ
diff --git a/web/struct_tree_layer_builder.js b/web/struct_tree_layer_builder.js
index 66e1f98cb..393191420 100644
--- a/web/struct_tree_layer_builder.js
+++ b/web/struct_tree_layer_builder.js
@@ -155,10 +155,7 @@ class MathMLSanitizer {
               "accentunder",
               "columnspan",
               "rowspan",
-            ].map(name => ({
-              name,
-              namespace: MathMLNamespace,
-            })),
+            ],
             comments: false,
           })
         : null