diff --git a/src/doc/rustc-dev-guide/.github/workflows/ci.yml b/src/doc/rustc-dev-guide/.github/workflows/ci.yml
index 415d0dc397dc..daf5223cbd4a 100644
--- a/src/doc/rustc-dev-guide/.github/workflows/ci.yml
+++ b/src/doc/rustc-dev-guide/.github/workflows/ci.yml
@@ -14,7 +14,7 @@ jobs:
     if: github.repository == 'rust-lang/rustc-dev-guide'
     runs-on: ubuntu-latest
     env:
-      MDBOOK_VERSION: 0.4.21
+      MDBOOK_VERSION: 0.4.48
       MDBOOK_LINKCHECK2_VERSION: 0.9.1
       MDBOOK_MERMAID_VERSION: 0.12.6
       MDBOOK_TOC_VERSION: 0.11.2