1 files changed, 4 insertions, 1 deletions

diff --git a/archival/libarchive/decompress_unlzma.c b/archival/libarchive/decompress_unlzma.c
index 0744f231a..fb5aac8fe 100644
--- a/archival/libarchive/decompress_unlzma.c
+++ b/archival/libarchive/decompress_unlzma.c
@@ -290,8 +290,11 @@ unpack_lzma_stream(transformer_state_t *xstate)
                                 uint32_t pos;
 
                                 pos = buffer_pos - rep0;
-                                if ((int32_t)pos < 0)
+                                if ((int32_t)pos < 0) {
                                         pos += header.dict_size;
+                                        if ((int32_t)pos < 0)
+                                                goto bad;
+                                }
                                 match_byte = buffer[pos];
                                 do {
                                         int bit;