diff --git a/ChangeLog b/ChangeLog
index 66ecf9783..dc92e241a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -8,6 +8,8 @@ Features
      https://sweet32.info/SWEET32_CCS16.pdf.
 
 Bugfix
+   * Fix 1-byte buffer overflow in mbedtls_mpi_write_string() when
+     used with negative inputs. Found by Guido Vranken in #2404.
    * Fix a compilation issue with mbedtls_ecp_restart_ctx not being defined
      when MBEDTLS_ECP_ALT is defined. Reported by jwhui. Fixes #2242.
    * Run the AD too long test only if MBEDTLS_CCM_ALT is not defined.