diff --git a/packages/producer/src/services/htmlCompiler.fontEmbed.test.ts b/packages/producer/src/services/htmlCompiler.fontEmbed.test.ts
new file mode 100644
index 000000000..494f35525
--- /dev/null
+++ b/packages/producer/src/services/htmlCompiler.fontEmbed.test.ts
@@ -0,0 +1,49 @@
+import { describe, expect, it } from "vitest";
+import { urlOccurrenceRe } from "./htmlCompiler.js";
+
+/**
+ * The embed step used `result.replaceAll(localPath, dataUri)` — a bare
+ * substring rewrite over the whole compiled document. These pin the collision
+ * that made unsafe: it is invisible in ordinary projects and easy to
+ * reintroduce, because the naive form passes every test that uses one font.
+ */
+describe("font embed url() anchoring", () => {
+  const DATA_URI = "data:font/woff2;base64,AAAA";
+  const replace = (html: string, path: string) =>
+    html.replace(urlOccurrenceRe(path), `url("${DATA_URI}")`);
+
+  it("rewrites the exact occurrence, quoted or bare", () => {
+    expect(replace(`src: url("fonts/x.ttf")`, "fonts/x.ttf")).toBe(`src: url("${DATA_URI}")`);
+    expect(replace(`src: url(fonts/x.ttf)`, "fonts/x.ttf")).toBe(`src: url("${DATA_URI}")`);
+    expect(replace(`src: url('fonts/x.ttf')`, "fonts/x.ttf")).toBe(`src: url("${DATA_URI}")`);
+  });
+
+  it("does not corrupt a longer url whose tail matches the embedded path", () => {
+    // The reported corruption: embedding `fonts/x.ttf` rewrote the tail of an
+    // untouched absolute rule, producing `url("file:///abs/<data-uri>")`.
+    const html = `a { src: url("fonts/x.ttf") } b { src: url("file:///abs/fonts/x.ttf") }`;
+    const out = replace(html, "fonts/x.ttf");
+    expect(out).toContain(`a { src: url("${DATA_URI}") }`);
+    expect(out).toContain(`b { src: url("file:///abs/fonts/x.ttf") }`);
+  });
+
+  it("does not corrupt a sibling whose path is a suffix of another project path", () => {
+    // No file:// needed. Any two paths where one is a suffix of the other
+    // collide under a bare substring replace.
+    const html = `a { src: url("img/logo.ttf") } b { src: url("assets/img/logo.ttf") }`;
+    const out = replace(html, "img/logo.ttf");
+    expect(out).toContain(`a { src: url("${DATA_URI}") }`);
+    expect(out).toContain(`b { src: url("assets/img/logo.ttf") }`);
+  });
+
+  it("leaves the path alone outside a url() wrapper", () => {
+    const html = `/* see fonts/x.ttf for the source */ a { src: url("fonts/x.ttf") }`;
+    const out = replace(html, "fonts/x.ttf");
+    expect(out).toContain("/* see fonts/x.ttf for the source */");
+  });
+
+  it("treats regex metacharacters in a path literally", () => {
+    const html = `a { src: url("fonts/x+y(1).ttf") }`;
+    expect(replace(html, "fonts/x+y(1).ttf")).toBe(`a { src: url("${DATA_URI}") }`);
+  });
+});
diff --git a/packages/producer/src/services/htmlCompiler.ts b/packages/producer/src/services/htmlCompiler.ts
index e279aebcb..5cbcd62d8 100644
--- a/packages/producer/src/services/htmlCompiler.ts
+++ b/packages/producer/src/services/htmlCompiler.ts
@@ -1668,7 +1668,21 @@ export async function localizeRemoteFontFaces(
   );
 }
 
-const LOCAL_FONTFACE_URL_RE = /url\(["']?(?!data:|https?:\/\/)([^"')]+)["']?\)/gi;
+// `file:` joins data: and http(s): in the exclusion list. Without it an
+// absolute `file:///abs/path/font.ttf` src was read as a project-RELATIVE path,
+// resolved to `<projectDir>/file:/abs/path/...`, and the failed read was
+// swallowed below — leaving the rule untouched for the browser to reject.
+const LOCAL_FONTFACE_URL_RE = /url\(["']?(?!data:|file:|https?:\/\/)([^"')]+)["']?\)/gi;
+
+/**
+ * Match one `url(<path>)` occurrence, with or without quotes, for a literal
+ * path. Exported for tests: the suffix-collision it prevents is invisible in
+ * ordinary projects and easy to reintroduce.
+ */
+export function urlOccurrenceRe(localPath: string): RegExp {
+  const escaped = localPath.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+  return new RegExp(`url\\((["']?)${escaped}\\1\\)`, "g");
+}
 // Base64 expands bytes by ~33%, then immutable HTML replacements retain more
 // string copies while compiling. Files up to and including 5 MiB remain inline;
 // the first byte above that stays file-backed. This conservative ceiling keeps
@@ -1739,10 +1753,26 @@ async function embedLocalFontFaces(html: string, projectDir: string): Promise<st
               `[Compiler] Embedded local font file: ${localPath} (${(font.buffer.length / 1024).toFixed(0)} KB → data URI)`,
             );
           }
-          result = result.replaceAll(localPath, dataUri);
+          // Anchored on the `url(...)` occurrence, not a bare substring. A
+          // plain replaceAll of `localPath` also rewrites that text anywhere
+          // else it appears -- including inside a LONGER url whose tail
+          // happens to match, e.g. embedding `fonts/x.ttf` would corrupt an
+          // untouched `url("file:///abs/fonts/x.ttf")` into
+          // `url("file:///abs/<data-uri>")`. Any two paths where one is a
+          // suffix of the other collide the same way. Every sibling rewrite
+          // in this file already anchors like this.
+          result = result.replace(urlOccurrenceRe(localPath), `url("${dataUri}")`);
           embeddedPaths.add(localPath);
-        } catch {
-          // File read or compression failed — keep the original path
+        } catch (error) {
+          // Keep the original path: a font that cannot be read must not fail
+          // the render. Logged rather than silently swallowed -- a silent skip
+          // here means the composition renders in a fallback typeface and
+          // nothing says why.
+          defaultLogger.warn(
+            `[Compiler] Could not embed local font ${localPath}: ${
+              error instanceof Error ? error.message : String(error)
+            }`,
+          );
         }
       }
     }