gzip: fix CVE-2026-41992

Backport upstream fix for a global buffer overflow in the LZH
decompression logic (unlzh.c). The left[] and right[] global arrays
shared across LZW and LZH decompression routines are not reinitialized
between files processed in the same invocation, allowing an
out-of-bounds read in the LZH decoder.

Adapted for gzip 1.13:
- Refreshed NEWS and THANKS hunks to match 1.13 release context.

Reference: https://nvd.nist.gov/vuln/detail/CVE-2026-41992
(From OE-Core rev: db470c65798b4a90a5c1c333d61f3a531cca75cc)

Signed-off-by: Jaipaul Cheernam <jaipaul.cheernam@est.tech>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit deaaaacabbf8d21fb9271e3f6f83055893510cff)
Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
Signed-off-by: Paul Barker <paul@pbarker.dev>

meta/recipes-extended/gzip/gzip-1.13/CVE-2026-41992.patch

@@ -0,0 +1,64 @@
+From 63dbf6b3b9e6e781df1a6a64e609b10e23969681 Mon Sep 17 00:00:00 2001
+From: Paul Eggert <eggert@cs.ucla.edu>
+Date: Wed, 15 Apr 2026 12:00:17 -0700
+Subject: =?UTF-8?q?gzip:=20don=E2=80=99t=20mishandle=20.lzh=20after=20.Z?=
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Problem reported by Michał Majchrowicz.
+* unlzh.c (read_c_len): Clear left and right when n == 0.
+
+CVE: CVE-2026-41992
+Upstream-Status: Backport [https://cgit.git.savannah.gnu.org/cgit/gzip.git/commit/?id=63dbf6b3b9e6e781df1a6a64e609b10e23969681]
+Signed-off-by: Jaipaul Cheernam <jaipaul.cheernam@est.tech>
+---
+ NEWS    | 4 ++++
+ THANKS  | 1 +
+ unlzh.c | 6 ++++++
+ 3 files changed, 11 insertions(+)
+
+diff --git a/NEWS b/NEWS
+index bdb7cc0..af2a08f 100644
+--- a/NEWS
++++ b/NEWS
+@@ -14,6 +14,10 @@ GNU gzip NEWS                                    -*- outline -*-
+ 
+ ** Bug fixes
+ 
++  A buffer overflow has been fixed when decompressing an .lzh file
++  after decompressing a .Z file.
++  [bug present since the beginning]
++
+   'gzip -d' no longer fails to report invalid compressed data
+   that uses a dictionary distance outside the input window.
+   [bug present since the beginning]
+diff --git a/THANKS b/THANKS
+index 4e545d9..a7d25e4 100644
+--- a/THANKS
++++ b/THANKS
+@@ -186,6 +186,7 @@ Jamie Lokier            u90jl@ecs.oxford.ac.uk
+ Richard Lloyd           R.K.Lloyd@csc.liv.ac.uk
+ David J. MacKenzie	djm@eng.umd.edu
+ John R MacMillan        john@chance.gts.org
++Michał Majchrowicz	mmajchrowicz@afine.com
+ Ron Male                male@eso.mc.xerox.com
+ Jakub Martisko		jamartis@redhat.com
+ Don R. Maszle           maze@bea.lbl.gov
+diff --git a/unlzh.c b/unlzh.c
+index 3320196..a6cf109 100644
+--- a/unlzh.c
++++ b/unlzh.c
+@@ -232,6 +232,12 @@ read_c_len ()
+         c = getbits(CBIT);
+         for (i = 0; i < NC; i++) c_len[i] = 0;
+         for (i = 0; i < 4096; i++) c_table[i] = c;
++
++        /* Needed in case LEFT and RIGHT are reused from a previous
++           LZW decompression.  It may be overkill to clear all of both
++           arrays, but nobody has had time to analyze this carefully.  */
++        memzero(left, (2 * NC - 1) * sizeof *left);
++        memzero(right, (2 * NC - 1) * sizeof *left);
+     } else {
+         i = 0;
+         while (i < n) {

meta/recipes-extended/gzip/gzip_1.13.bb

@@ -6,6 +6,7 @@ LICENSE = "GPL-3.0-or-later"
 
 SRC_URI = "${GNU_MIRROR}/gzip/${BP}.tar.gz \
            file://run-ptest \
+           file://CVE-2026-41992.patch \
            "
 SRC_URI:append:class-target = " file://wrong-path-fix.patch"