diff --git a/mozilla/nsprpub/pr/src/io/prlog.c b/mozilla/nsprpub/pr/src/io/prlog.c
index 67106453c3f..fea940c6b1a 100644
--- a/mozilla/nsprpub/pr/src/io/prlog.c
+++ b/mozilla/nsprpub/pr/src/io/prlog.c
@@ -219,7 +219,7 @@ void _PR_InitLog(void)
         PRInt32 bufSize = DEFAULT_BUF_SIZE;
         while (pos < evlen) {
             PRIntn level = 1, count = 0, delta = 0;
-            count = sscanf(&ev[pos], "%63[ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789]%n:%d%n",
+            count = sscanf(&ev[pos], "%63[ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_]%n:%d%n",
                            module, &delta, &level, &delta);
             pos += delta;
             if (count == 0) break;
@@ -328,7 +328,7 @@ static void _PR_SetLogModuleLevel( PRLogModuleInfo *lm )
         while (pos < evlen) {
             PRIntn level = 1, count = 0, delta = 0;
 
-            count = sscanf(&ev[pos], "%63[ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789]%n:%d%n",
+            count = sscanf(&ev[pos], "%63[ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_]%n:%d%n",
                            module, &delta, &level, &delta);
             pos += delta;
             if (count == 0) break;