From 12a6206864a0ba38dc506644bdb3928beea5256a Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 10 Aug 2026 06:38:17 -0700
Subject: [PATCH] Guard against overlength time zone abbreviations in
 to_char().

While typical abbreviations are only a few bytes long, a user-supplied
time_zone setting could specify a much longer abbreviation, enough to
overflow to_char's allocation of 12 bytes per format character. If so,
throw an error in the same style as commit 9241c84cb (CVE-2015-0241).

Reported-by: Hcamael <baiyjrh@gmail.com>
Reported-by: Amjad Shahzad <amjadshahzad2000@gmail.com>
Reported-by: Tan Zhen of AntAISecurityLab <TanZhen.AntAI@outlook.com>
Reported-by: Tomer Fichman <tomer@irregular.com>
Reported-by: Zheng Yu <zheng@depthfirst.com>
Reported-by: Amy Burnett (OpenAI Codex Security)
Reported-by: Rick de Jager <rick@v12.sh>
Reported-by: Heewon Song <asteria121@78researchlab.com>
Reported-by: Sylvie Mayer <smayer@cloudflare.com>
Reported-by: Aleksander Alekseev <aleksander@tigerdata.com>
Reported-by: Hillai Ben Sasson <hillai.bensasson@wiz.io>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Backpatch-through: 14
Security: CVE-2026-14669
---
 src/backend/utils/adt/formatting.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 54213afb05a..d9183509aa0 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -2996,10 +2996,18 @@ DCH_to_char(FormatNode *node, bool is_interval, TmToChar *in, char *out, Oid col
 				INVALID_FOR_INTERVAL;
 				if (tmtcTzn(in))
 				{
-					/* We assume here that timezone names aren't localized */
+					/*
+					 * We assume here that timezone abbreviations aren't
+					 * localized, so ASCII-only downcasing is sufficient.
+					 */
 					char	   *p = asc_tolower_z(tmtcTzn(in));
 
-					strcpy(s, p);
+					if (strlen(p) <= n->key->len * DCH_MAX_ITEM_SIZ)
+						strcpy(s, p);
+					else
+						ereport(ERROR,
+								(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+								 errmsg("time zone format value too long")));
 					pfree(p);
 					s += strlen(s);
 				}
@@ -3008,7 +3016,14 @@ DCH_to_char(FormatNode *node, bool is_interval, TmToChar *in, char *out, Oid col
 				INVALID_FOR_INTERVAL;
 				if (tmtcTzn(in))
 				{
-					strcpy(s, tmtcTzn(in));
+					const char *p = tmtcTzn(in);
+
+					if (strlen(p) <= n->key->len * DCH_MAX_ITEM_SIZ)
+						strcpy(s, p);
+					else
+						ereport(ERROR,
+								(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+								 errmsg("time zone format value too long")));
 					s += strlen(s);
 				}
 				break;