From 371a726043074b7c3f86c47107e38ab1f5462ed8 Mon Sep 17 00:00:00 2001
From: Osamaali313 <s.osamaali72@gmail.com>
Date: Tue, 11 Aug 2026 22:44:45 +0300
Subject: [PATCH] fix: message-parser timestamps overflow for dates from 2038
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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`<t:...>` timestamps parsed the epoch seconds with `(... / 1000) | 0`.
The `| 0` coerces to a signed 32-bit integer, so any date at or after
2038-01-19 03:14:07 UTC wraps to a negative value — e.g.
`<t:2040-01-01T00:00:00.000+00:00>` became -2085978496, which the
renderer shows as a 1903 date instead of 2040.

Use `Math.floor` instead of `| 0` in both `timestampFromIsoTime` and the
sibling `timestampFromHours`. For all in-range dates the result is
identical (the inputs are non-negative, so floor and truncation agree),
so this only fixes the overflow. Added a regression test past the 2038
boundary.
---
 .changeset/fix-message-parser-timestamp-overflow.md |  5 +++++
 packages/message-parser/src/utils.ts                | 10 +++++-----
 packages/message-parser/tests/timestamp.test.ts     |  3 +++
 3 files changed, 13 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/fix-message-parser-timestamp-overflow.md

diff --git a/.changeset/fix-message-parser-timestamp-overflow.md b/.changeset/fix-message-parser-timestamp-overflow.md
new file mode 100644
index 0000000000000..0a6feb3890b01
--- /dev/null
+++ b/.changeset/fix-message-parser-timestamp-overflow.md
@@ -0,0 +1,5 @@
+---
+'@rocket.chat/message-parser': patch
+---
+
+Fixes `<t:...>` timestamps with dates on or after 2038-01-19 rendering as a wrong (1903) date. The parser truncated the epoch seconds with `| 0`, which overflows the 32-bit signed range; it now uses `Math.floor`, so future dates parse correctly.
diff --git a/packages/message-parser/src/utils.ts b/packages/message-parser/src/utils.ts
index 8fa65001c76f1..516cbe7dc51ac 100644
--- a/packages/message-parser/src/utils.ts
+++ b/packages/message-parser/src/utils.ts
@@ -363,7 +363,7 @@ export const timestampFromHours = (hours: string, minutes = '00', seconds = '00'
 
 	const yearMonthDay = date.toISOString().split('T')[0];
 
-	const timestamp = (new Date(`${yearMonthDay}T${hours}:${minutes}:${seconds}${timezone}`).getTime() / 1000) | 0;
+	const timestamp = Math.floor(new Date(`${yearMonthDay}T${hours}:${minutes}:${seconds}${timezone}`).getTime() / 1000);
 
 	return timestamp.toString();
 };
@@ -387,9 +387,9 @@ export const timestampFromIsoTime = ({
 	milliseconds?: string;
 	timezone?: string;
 }) => {
-	const date =
-		(new Date(`${year}-${month}-${day}T${hours}:${minutes}:${seconds}.${milliseconds || '000'}${timezone ? `${timezone}` : ''}`).getTime() /
-			1000) |
-		0;
+	const date = Math.floor(
+		new Date(`${year}-${month}-${day}T${hours}:${minutes}:${seconds}.${milliseconds || '000'}${timezone ? `${timezone}` : ''}`).getTime() /
+			1000,
+	);
 	return date.toString();
 };
diff --git a/packages/message-parser/tests/timestamp.test.ts b/packages/message-parser/tests/timestamp.test.ts
index 6e6eab6ccab32..c177e690082f9 100644
--- a/packages/message-parser/tests/timestamp.test.ts
+++ b/packages/message-parser/tests/timestamp.test.ts
@@ -53,6 +53,9 @@ test.each([
 	['<t:2025-07-22T10:00:00.000+00:00:R>', '1753178400', 'R' as const],
 	['<t:2025-07-22T10:00:00+00:00:R>', '1753178400', 'R' as const],
 	['<t:2025-07-24T20:19:58.154+00:00:R>', '1753388398', 'R' as const],
+	// Beyond the 2038-01-19 32-bit boundary: must not overflow to a negative
+	// (previously `| 0` turned this into -2085978496 -> a 1903 date).
+	['<t:2040-01-01T00:00:00.000+00:00:R>', '2208988800', 'R' as const],
 ])('parses %p', (input, value, format) => {
 	const node = timestampNode(value, format, [0, input.length]);
 	expect(parse(input)).toEqual([paragraph([node])]);