diff --git a/neqo-transport/Cargo.toml b/neqo-transport/Cargo.toml
index 6095f3ac92..2abdbbfd95 100644
--- a/neqo-transport/Cargo.toml
+++ b/neqo-transport/Cargo.toml
@@ -14,7 +14,7 @@ workspace = true
 [dependencies]
 # Sync with https://searchfox.org/mozilla-central/source/Cargo.lock 2024-02-08
 enum-map = { version = "2.7", default-features = false }
-indexmap = { version = "1.9", default-features = false }
+indexmap = { version = "2.2", default-features = false } # See https://github.com/mozilla/neqo/issues/1858
 log = { workspace = true }
 neqo-common = { path = "../neqo-common" }
 neqo-crypto = { path = "../neqo-crypto" }