diff mbox series

[scarthgap] gzip: fix CVE-2026-41992

Message ID 20260707143421.34255-2-jaipaul.cheernam@est.tech
State Under Review
Delegated to: Yoann Congal
Headers show
Series [scarthgap] gzip: fix CVE-2026-41992 | expand

Commit Message

Jaipaul Cheernam July 7, 2026, 2:34 p.m. UTC 
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.

Reference: https://nvd.nist.gov/vuln/detail/CVE-2026-41992
Signed-off-by: Jaipaul Cheernam <jaipaul.cheernam@est.tech>
---
 .../gzip/gzip-1.13/CVE-2026-41992.patch       | 32 +++++++++++++++++++
 meta/recipes-extended/gzip/gzip_1.13.bb       |  1 +
 2 files changed, 33 insertions(+)
 create mode 100644 meta/recipes-extended/gzip/gzip-1.13/CVE-2026-41992.patch
diff mbox series

Patch

diff --git a/meta/recipes-extended/gzip/gzip-1.13/CVE-2026-41992.patch b/meta/recipes-extended/gzip/gzip-1.13/CVE-2026-41992.patch
new file mode 100644
index 0000000000..5d3534fcb1
--- /dev/null
+++ b/meta/recipes-extended/gzip/gzip-1.13/CVE-2026-41992.patch
@@ -0,0 +1,32 @@ 
+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: gzip: don't mishandle .lzh after .Z
+
+Problem reported by Michal 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>
+---
+ unlzh.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+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) {
diff --git a/meta/recipes-extended/gzip/gzip_1.13.bb b/meta/recipes-extended/gzip/gzip_1.13.bb
index fd846b30a5..208220867a 100644
--- a/meta/recipes-extended/gzip/gzip_1.13.bb
+++ b/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"