diff --git a/src/python/html_filter.py b/src/python/html_filter.py
index ba126855..2e9f3d7d 100644
--- a/src/python/html_filter.py
+++ b/src/python/html_filter.py
@@ -12,8 +12,8 @@ from html_sanitizer.sanitizer import Sanitizer
class HtmlFilter:
link_regexes = [re.compile(r, re.IGNORECASE) for r in [
- (r"(?P.+://(?P[a-z0-9._-]+)(?:/[/\-_.,a-z0-9%&?;=~]*)?"
- r"(?:\([/\-_.,a-z0-9%&?;=~]*\))?)"),
+ (r"(?P[a-zA-Z\d]+://(?P[a-z\d._-]+)"
+ r"(?:/[/\-_.,a-z\d%&?;=~]*)?(?:\([/\-_.,a-z\d%&?;=~]*\))?)"),
r"mailto:(?P[a-z0-9._-]+@(?P[a-z0-9_.-]+[a-z]))",
r"tel:(?P[0-9+-]+)(?P)",
r"(?Pmagnet:\?xt=urn:[a-z0-9]+:.+)(?P)",