From 86dfdbee1fb97f8e8cfaec9a212d6d27672d661e Mon Sep 17 00:00:00 2001
From: Tyler Yankee <tyler.yankee@kitware.com>
Date: Sun, 26 Apr 2026 17:50:30 -0400
Subject: [PATCH] libarchive: Backport "Fix use of uninitialized values from
 Huffman table"

Backport libarchive commit `1f5454575f` (cab reader: Fix use of
uninitialized values from Huffman, 2026-04-23).

Add a fuzzing test case to expose this to dynamic analysis tools.
---
 .../Fuzzing/corpus/archive/cab-huffman-uninit.tar | Bin 0 -> 256 bytes
 .../libarchive/archive_read_support_format_cab.c  |   4 ++++
 2 files changed, 4 insertions(+)
 create mode 100644 Tests/Fuzzing/corpus/archive/cab-huffman-uninit.tar

diff --git a/Tests/Fuzzing/corpus/archive/cab-huffman-uninit.tar b/Tests/Fuzzing/corpus/archive/cab-huffman-uninit.tar
new file mode 100644
index 0000000000000000000000000000000000000000..2bcd3fd315f0e62e2ef303ecbd3a09d03bc58751
GIT binary patch
literal 256
zcmeYbc6MU`0_NBW(FPV4Mn)hG14BbS10xVRfH_NnB>R75A<ks|g2dwD@)WQrkZ@pN
z2=HcP%7`=c3Dncz3gFV?RN&Gt%_~kVQ7|?!FtRW*HZ!v{GO#qZFflU*B4cwCGXrxI
zV?%Q@3nN3{s0v1YMuy#30fVzI%o+w028O>1Ku0nB|Np;UA1+J;gV_cM7=9wFEItC{
MEnwgPVns$L05M=Q6#xJL

literal 0
HcmV?d00001

diff --git a/Utilities/cmlibarchive/libarchive/archive_read_support_format_cab.c b/Utilities/cmlibarchive/libarchive/archive_read_support_format_cab.c
index 56d1c2bff2..594369468d 100644
--- a/Utilities/cmlibarchive/libarchive/archive_read_support_format_cab.c
+++ b/Utilities/cmlibarchive/libarchive/archive_read_support_format_cab.c
@@ -3201,6 +3201,10 @@ lzx_make_huffman_table(struct huffman *hf)
 	bitlen = hf->bitlen;
 	len_avail = hf->len_size;
 	hf->tree_used = 0;
+	/* Initialize table to invalid values */
+	for (i = 0; i < tbl_size; i++) {
+		tbl[i] = (uint16_t)hf->len_size;
+	}
 	for (i = 0; i < len_avail; i++) {
 		uint16_t *p;
 		int len, cnt;