From 19a01d092688d0c99d29bd4a587c5ba76fb2bc3b Mon Sep 17 00:00:00 2001
From: Miod Vallat <miod.vallat@powerdns.com>
Date: Wed, 4 Feb 2026 07:00:16 +0100
Subject: [PATCH] Correctly compute public key exponent length when larger than
 255.

Signed-off-by: Miod Vallat <miod.vallat@powerdns.com>
---
 pdns/opensslsigners.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pdns/opensslsigners.cc b/pdns/opensslsigners.cc
index 3a8df543b1..fb4daf6aec 100644
--- a/pdns/opensslsigners.cc
+++ b/pdns/opensslsigners.cc
@@ -941,7 +941,7 @@ void OpenSSLRSADNSCryptoKeyEngine::fromPublicKeyString(const std::string& conten
     if (contentLen < 3) {
       throw runtime_error(getName() + " invalid input size for the public key");
     }
-    const size_t exponentSize = raw[1] * 0xff + raw[2];
+    const size_t exponentSize = (static_cast<size_t>(raw[1])) * 0x100 + raw[2];
     if (contentLen < (exponentSize + 4)) {
       throw runtime_error(getName() + " invalid input size for the public key");
     }
-- 
2.47.3