From 9ad74926d4f7f34ff902e1db5235535aa813c33f Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Mon, 6 Apr 2026 22:22:43 +0100
Subject: [PATCH] Fix 1-byte buffer overflow in relay_reply4()

Potential SIGSEGV when using DHCPv4-relay.

Thanks to Asim Viladi Oglu Manizada for finding this.
---
 src/rfc2131.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git src/rfc2131.c b/src/rfc2131.c
index 7bdfefd..55aad03 100644
--- src/rfc2131.c
+++ src/rfc2131.c
@@ -3248,7 +3248,7 @@ unsigned int relay_reply4(struct dhcp_packet *mess, size_t sz, char *arrival_int
 
 	      /* delete agent info before return RFC 3046 para 2.1 */
 	      *opt = OPTION_END;
-	      memset(opt + 1, 0, option_len(opt) + 2);
+	      memset(opt + 1, 0, option_len(opt) + 1);
 	    }
 	}
       else if (mess->giaddr.s_addr == relay->local.addr4.s_addr)
-- 
2.20.1

