diff --git a/README.md b/README.md
index 8b5b60e..a9f3145 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,10 @@ red PR job against.
 
 - `scripts/check-links.sh [--external-warn]` — resolves every internal link/anchor and
   probes external URLs (CI runs it with `--external-warn` on PRs and pushes; the weekly
-  scheduled run and manual dispatch hard-fail on broken external links).
+  scheduled run and manual dispatch hard-fail on broken external links). Besides every
+  committed page and the `make-redirects.sh` map, it checks the URI fields of
+  `.well-known/security.txt` (RFC 9116 `Contact`, `Canonical`, `Policy`,
+  `Acknowledgments`, `Hiring`), so a rotted security-contact link is reported too.
 - `scripts/check-links.test.sh` — fixture-based self-test of the link checker; runs
   offline (fake `curl`).
 - `node --test scripts/story-dialog.test.mjs` — runs the Share-your-story dialog script
diff --git a/scripts/check-links.sh b/scripts/check-links.sh
index f4f1fae..fd111cc 100755
--- a/scripts/check-links.sh
+++ b/scripts/check-links.sh
@@ -75,12 +75,23 @@ extract_redirect_targets() {
   awk -F'"' '/^[[:space:]]*\[[^]]+\]="/ { split($2, parts, "|"); print "make-redirects.sh\t" parts[1] }' "$redirects"
 }
 
+# RFC 9116 §2.5: the values of these security.txt fields are URIs. Comment
+# lines (#) and non-URI fields (Expires, Preferred-Languages) are left alone.
+extract_security_txt_uris() {
+  local file=".well-known/security.txt"
+  [[ -f "$ROOT/$file" ]] || return 0
+  grep -Ei '^(Contact|Canonical|Policy|Acknowledgments|Hiring):' "$ROOT/$file" |
+    sed -E -e 's/^[^:]+:[[:space:]]*//' -e 's/[[:space:]]+$//' |
+    awk -v file="$file" 'NF { print file "\t" $0 }'
+}
+
 find "$ROOT" -name '*.html' -not -path "$WORK_DIR/*" -print | sort |
   while IFS= read -r file; do
     rel="${file#$ROOT/}"
     extract_html_links "$rel"
   done > "$WORK_DIR/links.tsv"
 extract_redirect_targets >> "$WORK_DIR/links.tsv"
+extract_security_txt_uris >> "$WORK_DIR/links.tsv"
 
 sort -u "$WORK_DIR/links.tsv" > "$WORK_DIR/links.dedup.tsv"
 
diff --git a/scripts/check-links.test.sh b/scripts/check-links.test.sh
index 7d3c030..47b3172 100755
--- a/scripts/check-links.test.sh
+++ b/scripts/check-links.test.sh
@@ -165,6 +165,47 @@ expect_out 'ERROR external broken: make-redirects\.sh -> https://example\.test/b
 expect_no_out 'label' "label half is not treated as a URL"
 expect_out 'External failures: 1\.' "only the broken target counts"
 
+echo "case: .well-known/security.txt URI fields are checked (RFC 9116 Contact/Canonical/Policy/Acknowledgments/Hiring)"
+root="$(new_site security-txt)"
+echo '<p>home</p>' > "$root/index.html"
+mkdir -p "$root/.well-known"
+cat > "$root/.well-known/security.txt" <<'TXT'
+# A comment mentioning https://example.test/broken-comment must be ignored
+Contact: mailto:security@example.test
+Contact: https://example.test/broken
+Expires: 2027-01-01T00:00:00.000Z
+Preferred-Languages: en
+Canonical: https://hivecommons.dev/.well-known/security.txt
+Policy: https://example.test/fine
+Acknowledgments: https://example.test/soft404
+Hiring: https://example.test/server-error
+TXT
+run_checker "$root"
+expect_rc 1 "rotten security.txt URIs fail the gate"
+expect_out 'ERROR external broken: \.well-known/security\.txt -> https://example\.test/broken \(404' "https Contact is probed and attributed to security.txt"
+expect_out 'ERROR external soft-404: \.well-known/security\.txt -> https://example\.test/soft404 \(200' "Acknowledgments is probed"
+expect_out 'ERROR external broken: \.well-known/security\.txt -> https://example\.test/server-error \(500' "Hiring is probed"
+expect_no_out 'broken-comment' "comment lines are not harvested"
+expect_no_out 'mailto' "mailto: Contact is skipped, not flagged"
+expect_no_out 'internal target missing' "Canonical resolves to the committed security.txt"
+expect_out 'External failures: 3\.' "Policy that resolves is not counted"
+
+echo "case: security.txt Canonical pointing at a path the tree does not publish is an internal error"
+root="$(new_site security-canonical)"
+echo '<p>home</p>' > "$root/index.html"
+mkdir -p "$root/.well-known"
+printf 'Contact: mailto:security@example.test\nCanonical: https://hivecommons.dev/.well-known/other.txt\n' > "$root/.well-known/security.txt"
+run_checker "$root" --external-warn
+expect_rc 1 "unpublished Canonical fails even under --external-warn"
+expect_out 'ERROR internal target missing: \.well-known/security\.txt -> https://hivecommons\.dev/\.well-known/other\.txt' "Canonical is resolved against the tree like any site URL"
+
+echo "case: a site without security.txt is unaffected"
+root="$(new_site no-security-txt)"
+echo '<a href="/">home</a>' > "$root/index.html"
+run_checker "$root"
+expect_rc 0 "no security.txt, no extra links"
+expect_out 'Checked 1 unique links\.' "only the page link is counted"
+
 echo "case: external failures — hard 404, 5xx, curl failure, soft-404"
 root="$(new_site external)"
 cat > "$root/index.html" <<'HTML'