diff --git a/CHANGELOG.md b/CHANGELOG.md
index ad84b89..3eb641a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,30 @@ skip versions are the composition of each intervening adjacent
 release's steps in order — no A-to-B path is pre-computed beyond
 that.
 
+## 0.31.5 — 2026-06-03
+
+**Patch — supply-chain hygiene: pin security floors on two unbounded
+*transitive* dependencies so vulnerability scanners stay anchored to the
+patched range. No direct-import, schema, API, config, overlay, or secret
+change; deployed installs already satisfy these floors, so no rebuild or
+redeploy is required to become compliant. No upgrade steps.**
+
+`backend/requirements.txt` declares only loose (`>=`) direct constraints
+and ships no compiled lockfile. osv-scanner v2 resolves the *transitive*
+graph and, for any unpinned transitive package, pins it to its **minimum**
+published version — surfacing CVEs in ancient releases that `pip install`
+would never actually choose. Two such phantoms were firing:
+
+- **`tqdm`** (pulled by `google-generativeai`) resolved to `4.9.0` (2016),
+  flagging `GHSA-r7q7-xcjw-qx8q` (HIGH) and friends — fixed in 4.66.3.
+- **`idna`** (pulled by `httpx` / `anthropic`) resolved to `3.9.0`,
+  flagging `GHSA-65pc-fj4g-8rjx` — fixed in 3.15.
+
+Adding `tqdm>=4.66.3` and `idna>=3.15` anchors the resolver to the patched
+range. The live deployment already runs patched versions (e.g. tqdm 4.67.x);
+this only corrects what the scanner *sees*. The proper long-term fix is a
+fully-compiled lockfile — tracked separately.
+
 ## 0.31.4 — 2026-06-01
 
 **Patch — bug fix + UI polish: secondary buttons that were invisible on
diff --git a/VERSION b/VERSION
index a8a0217..5f94ce0 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.31.4
+0.31.5
diff --git a/backend/requirements.txt b/backend/requirements.txt
index 23ee1ee..bbead63 100644
--- a/backend/requirements.txt
+++ b/backend/requirements.txt
@@ -9,3 +9,12 @@ google-generativeai>=0.8
 openai>=1.50
 PyYAML>=6.0
 bcrypt>=4.2
+
+# Security floors on unbounded *transitive* deps (not direct imports). osv-scanner
+# resolves an unpinned transitive package to its MINIMUM PyPI version, which surfaces
+# CVEs in ancient releases pip would never actually install. These floors keep the
+# Patchwatch radar (and any scan) anchored to the patched range.
+#   tqdm <- google-generativeai ; GHSA-r7q7-xcjw-qx8q et al., fixed in 4.66.3
+#   idna <- httpx / anthropic   ; GHSA-65pc-fj4g-8rjx,        fixed in 3.15
+tqdm>=4.66.3
+idna>=3.15
diff --git a/frontend/package.json b/frontend/package.json
index ac13081..f3dc192 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -1,7 +1,7 @@
 {
   "name": "rfc-app-frontend",
   "private": true,
-  "version": "0.31.4",
+  "version": "0.31.5",
   "type": "module",
   "scripts": {
     "dev": "vite",