diff --git a/CHANGELOG.md b/CHANGELOG.md
index bd32eea869..b264401711 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,7 @@ Docs: https://docs.openclaw.ai
 ### Fixes
 
 - Security: replace deprecated SHA-1 sandbox configuration hashing with SHA-256 for deterministic sandbox cache identity and recreation checks. Thanks @kexinoh.
+- Security/Sessions: create new session transcript JSONL files with user-only (`0o600`) permissions and extend `openclaw security audit --fix` to remediate existing transcript file permissions.
 - Security/Logging: redact Telegram bot tokens from error messages and uncaught stack traces to prevent accidental secret leakage into logs. Thanks @aether-ai-agent.
 - Sandbox/Security: block dangerous sandbox Docker config (bind mounts, host networking, unconfined seccomp/apparmor) to prevent container escape via config injection. Thanks @aether-ai-agent.
 - Sandbox: preserve array order in config hashing so order-sensitive Docker/browser settings trigger container recreation correctly. Thanks @kexinoh.
diff --git a/src/config/sessions/sessions.test.ts b/src/config/sessions/sessions.test.ts
index f29ff5a7f2..39387b220f 100644
--- a/src/config/sessions/sessions.test.ts
+++ b/src/config/sessions/sessions.test.ts
@@ -183,6 +183,10 @@ describe("appendAssistantMessageToSessionTranscript", () => {
     expect(result.ok).toBe(true);
     if (result.ok) {
       expect(fs.existsSync(result.sessionFile)).toBe(true);
+      const sessionFileMode = fs.statSync(result.sessionFile).mode & 0o777;
+      if (process.platform !== "win32") {
+        expect(sessionFileMode).toBe(0o600);
+      }
 
       const lines = fs.readFileSync(result.sessionFile, "utf-8").trim().split("\n");
       expect(lines.length).toBe(2);
diff --git a/src/config/sessions/transcript.ts b/src/config/sessions/transcript.ts
index 659c089fce..9a20aa3c68 100644
--- a/src/config/sessions/transcript.ts
+++ b/src/config/sessions/transcript.ts
@@ -72,7 +72,10 @@ async function ensureSessionHeader(params: {
     timestamp: new Date().toISOString(),
     cwd: process.cwd(),
   };
-  await fs.promises.writeFile(params.sessionFile, `${JSON.stringify(header)}\n`, "utf-8");
+  await fs.promises.writeFile(params.sessionFile, `${JSON.stringify(header)}\n`, {
+    encoding: "utf-8",
+    mode: 0o600,
+  });
 }
 
 export async function appendAssistantMessageToSessionTranscript(params: {
diff --git a/src/gateway/server-methods/chat.ts b/src/gateway/server-methods/chat.ts
index 55b0d97dc6..1fe8d06bee 100644
--- a/src/gateway/server-methods/chat.ts
+++ b/src/gateway/server-methods/chat.ts
@@ -119,7 +119,10 @@ function ensureTranscriptFile(params: { transcriptPath: string; sessionId: strin
       timestamp: new Date().toISOString(),
       cwd: process.cwd(),
     };
-    fs.writeFileSync(params.transcriptPath, `${JSON.stringify(header)}\n`, "utf-8");
+    fs.writeFileSync(params.transcriptPath, `${JSON.stringify(header)}\n`, {
+      encoding: "utf-8",
+      mode: 0o600,
+    });
     return { ok: true };
   } catch (err) {
     return { ok: false, error: err instanceof Error ? err.message : String(err) };
diff --git a/src/security/fix.test.ts b/src/security/fix.test.ts
index d9f691b47b..976b357b5d 100644
--- a/src/security/fix.test.ts
+++ b/src/security/fix.test.ts
@@ -255,6 +255,9 @@ describe("security fix", () => {
     const sessionsStorePath = path.join(sessionsDir, "sessions.json");
     await fs.writeFile(sessionsStorePath, "{}\n", "utf-8");
     await fs.chmod(sessionsStorePath, 0o644);
+    const transcriptPath = path.join(sessionsDir, "sess-main.jsonl");
+    await fs.writeFile(transcriptPath, '{"type":"session"}\n', "utf-8");
+    await fs.chmod(transcriptPath, 0o644);
 
     const env = {
       ...process.env,
@@ -269,6 +272,7 @@ describe("security fix", () => {
     expectPerms((await fs.stat(allowFromPath)).mode & 0o777, 0o600);
     expectPerms((await fs.stat(authProfilesPath)).mode & 0o777, 0o600);
     expectPerms((await fs.stat(sessionsStorePath)).mode & 0o777, 0o600);
+    expectPerms((await fs.stat(transcriptPath)).mode & 0o777, 0o600);
     expectPerms((await fs.stat(includePath)).mode & 0o777, 0o600);
   });
 });
diff --git a/src/security/fix.ts b/src/security/fix.ts
index f3a2e88cf8..085fcb525c 100644
--- a/src/security/fix.ts
+++ b/src/security/fix.ts
@@ -366,6 +366,21 @@ async function chmodCredentialsAndAgentState(params: {
     const storePath = path.join(sessionsDir, "sessions.json");
     // eslint-disable-next-line no-await-in-loop
     params.actions.push(await params.applyPerms({ path: storePath, mode: 0o600, require: "file" }));
+
+    // Fix permissions on session transcript files (*.jsonl)
+    // eslint-disable-next-line no-await-in-loop
+    const sessionEntries = await fs.readdir(sessionsDir, { withFileTypes: true }).catch(() => []);
+    for (const entry of sessionEntries) {
+      if (!entry.isFile()) {
+        continue;
+      }
+      if (!entry.name.endsWith(".jsonl")) {
+        continue;
+      }
+      const p = path.join(sessionsDir, entry.name);
+      // eslint-disable-next-line no-await-in-loop
+      params.actions.push(await params.applyPerms({ path: p, mode: 0o600, require: "file" }));
+    }
   }
 }