From 14fdad300178a4e8b3bb50182ee41fbf49aa0074 Mon Sep 17 00:00:00 2001
From: pedrofrxncx <pedro_vaz_franca@hotmail.com>
Date: Fri, 21 Aug 2026 00:20:00 -0300
Subject: [PATCH] fix(threads): sanitize object keys, not just values, before
 storing a part payload
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serializePayload's JSON.stringify replacer strips NUL bytes and lone
surrogates from string VALUES so a part payload never trips Postgres's
SQLSTATE 22P05 on INSERT. But a replacer function can only substitute a
key's mapped value, never the key text itself — an object key carrying a
NUL byte or an unpaired surrogate (e.g. a tool result keyed by
attacker/content-derived strings) still serializes to a raw \u0000 escape
and hits the exact same 22P05 this code exists to prevent, stranding the
run in_progress forever.

Adds sanitizeKeysForPg to rebuild the payload tree with clean keys before
stringifying. Normal keys are byte-identical (both regexes are no-ops on
clean input), so ids derived from the payload stay stable.
---
 .../src/storage/thread-message-parts.test.ts  | Bin 2470 -> 3058 bytes
 apps/api/src/storage/thread-message-parts.ts  |  15 ++++++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/apps/api/src/storage/thread-message-parts.test.ts b/apps/api/src/storage/thread-message-parts.test.ts
index 7448e8052efc5aa38c74df4aaa6a4f3702f04eb4..0005cf7a2454eba55651512d35d59ba27496583f 100644
GIT binary patch
delta 305
zcmZ1`{7HPnBF=g)1qFS51^=Y1)Z`L{?9|F)g}l_%6orzERE6Ti+*Ad>P#^u`(xRgL
z^u!XNP)Si{K|y9-I#@wjVoqslu|j%ki9%vhep#v>(6G!B4JELuVvtsaq{<SYinOBq
zT!nmu9Xbkm`6UWjrNt%e3J^mkH?S%SM<*mDrZ4~<kq~R8pahnfe4MpYO;fKV-?gwb
zF-N0X0jL6~04A-ZP^)PTv=u~7e#x%Do0*4X&t!HEJ*nt~oYcgWm{J!D0|OMJl_n>0
ecxpx~fu!H>-wTveiUrx^l&S%-TM2G7$anzD#AZ<d

delta 12
Tcmew)zD#(-B2JcCO=~UyAg=@s

diff --git a/apps/api/src/storage/thread-message-parts.ts b/apps/api/src/storage/thread-message-parts.ts
index 4f99b06727..fb3492a608 100644
--- a/apps/api/src/storage/thread-message-parts.ts
+++ b/apps/api/src/storage/thread-message-parts.ts
@@ -66,6 +66,19 @@ function sanitizeForPg(value: string): string {
   return value.replace(NUL, "").replace(LONE_SURROGATE, "\uFFFD");
 }
 
+// The replacer below only reaches values, never object keys.
+function sanitizeKeysForPg(value: unknown): unknown {
+  if (Array.isArray(value)) return value.map(sanitizeKeysForPg);
+  if (value !== null && typeof value === "object") {
+    const out: Record<string, unknown> = {};
+    for (const [key, v] of Object.entries(value)) {
+      out[sanitizeForPg(key)] = sanitizeKeysForPg(v);
+    }
+    return out;
+  }
+  return value;
+}
+
 export function serializePayload(payload: unknown): string {
   if (
     estimatePayloadBytes(payload, MAX_PART_PAYLOAD_BYTES) >
@@ -79,7 +92,7 @@ export function serializePayload(payload: unknown): string {
   // A JSON replacer visits every string in the payload tree; clean strings pass
   // through untouched (byte-identical output, so ids derived from the payload
   // stay stable).
-  return JSON.stringify(payload, (_key, value) =>
+  return JSON.stringify(sanitizeKeysForPg(payload), (_key, value) =>
     typeof value === "string" ? sanitizeForPg(value) : value,
   );
 }