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help / color / mirror / Atom feedFrom: Noah Misch <noah@leadboat.com>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Avoid passing unintended format codes to snprintf().
Date: Mon, 11 May 2026 12:19:37 +0000
Message-ID: <E1wMPbl-0002UP-1W@gemulon.postgresql.org> (raw)
Avoid passing unintended format codes to snprintf().
timeofday() assumed that the output of pg_strftime() could not contain
% signs, other than the one it explicitly asks for with %%. However,
we don't have that guarantee with respect to the time zone name (%Z).
A crafted time zone setting could abuse the subsequent snprintf()
call, resulting in crashes or disclosure of server memory.
To fix, split the pg_strftime() call into two and then treat the
outputs as literal strings, not a snprintf format string. The
extra pg_strftime() call doesn't really cost anything, since the
bulk of the conversion work was done by pg_localtime().
Also, adjust buffer widths so that we're not risking string truncation
during the snprintf() step, as that would create a hazard of producing
mis-encoded output.
This also fixes a latent portability issue: the format string expects
an int, but tp.tv_usec is long int on many platforms.
Reported-by: Xint Code
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: John Naylor <johncnaylorls@gmail.com>
Backpatch-through: 14
Security: CVE-2026-6474
Branch
------
REL_18_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/ba27389c2cfa1485bbe26754b23d3f6b4c4e72e2
Author: Tom Lane <tgl@sss.pgh.pa.us>
Modified Files
--------------
src/backend/utils/adt/timestamp.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: noah@leadboat.com, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Avoid passing unintended format codes to snprintf().
In-Reply-To: <E1wMPbl-0002UP-1W@gemulon.postgresql.org>
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