Add advisory for libcrux-ed25519

Author: jschneider-bensch

crates/libcrux-ed25519/RUSTSEC-0000-0000.md

@@ -0,0 +1,32 @@
+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "libcrux-ed25519"
+date = "2026-03-04"
+cvss = "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
+url = "https://github.com/cryspen/libcrux/pull/1349"
+
+[affected.functions]
+"libcrux_ed25519::generate_key_pair" = [ "<= 0.0.6" ]
+
+[versions]
+patched = [">= 0.0.7 "]
+```
+
+# All-Zero Key Generation on Catastrophic RNG Failure
+
+The libcrux-ed25519 key generation samples Ed25519 secret keys from a
+provided CSPRNG in a loop for up to 100 attempts until a non-zero key
+is found.  If a non-zero key could not be sampled within 100 attempts
+the key generation function would silently continue with an all-zero buffer as
+the secret key.
+
+## Impact
+This bug only occurs in the event of a catastrophic failure of the
+CSPRNG, but would allow anyone to forge signatures under the resulting
+static signing key.
+
+## Mitigation
+Instead of silently continuing with an all-zero signing key, starting
+from version `0.0.7` key generation will error in the case of 100
+failed attempts at sampling a valid key.