diff --git a/core/Decoder/Png/src/Png.cpp b/core/Decoder/Png/src/Png.cpp
index d137df164..cb04f25bd 100644
--- a/core/Decoder/Png/src/Png.cpp
+++ b/core/Decoder/Png/src/Png.cpp
@@ -138,9 +138,9 @@ std::optional<Header> ParseHeader(std::span<const std::uint8_t> png) {
     while (png.size() - offset >= CHUNK_OVERHEAD) {
         const std::uint32_t length = readBigEndian32(&png[offset]);
         const std::uint8_t* type = &png[offset + 4];
+        if (length > png.size() - offset - CHUNK_OVERHEAD) break;
         if (isChunkType(type, "tRNS")) header.hasTransparency = true;
         if (isChunkType(type, "tRNS") || isChunkType(type, "IDAT") || isChunkType(type, "IEND")) break;
-        if (length > png.size() - offset - CHUNK_OVERHEAD) break;
         offset += CHUNK_OVERHEAD + length;
     }
     return header;
diff --git a/core/Decoder/Png/tests/Png.cpp b/core/Decoder/Png/tests/Png.cpp
index 7287ed5b3..0c1ac81d1 100644
--- a/core/Decoder/Png/tests/Png.cpp
+++ b/core/Decoder/Png/tests/Png.cpp
@@ -153,6 +153,12 @@ int main() {
     Require(paletteHeader.has_value());
     Require(paletteHeader->width == 2 && paletteHeader->height == 2 && paletteHeader->bitDepth == 2);
     Require(paletteHeader->colorType == Decoder::Png::ColorType::Palette && paletteHeader->hasTransparency);
+    for (const std::size_t size : {std::size_t{69}, std::size_t{71}}) {
+        const auto truncated = Decoder::Png::ParseHeader(std::span<const std::uint8_t>(PALETTE_TRNS, size));
+        Require(truncated.has_value() && !truncated->hasTransparency);
+    }
+    const auto completeTransparency = Decoder::Png::ParseHeader(std::span<const std::uint8_t>(PALETTE_TRNS, 73));
+    Require(completeTransparency.has_value() && completeTransparency->hasTransparency);
     const auto palette = Decoder::Png::Decode(PALETTE_TRNS);
     Require(palette.has_value());
     Require(palette->pixels == std::vector<std::uint8_t>({255, 0, 0, 255, 0, 255, 0, 0, 0, 0, 255, 255, 255, 255, 0, 128}));
diff --git a/core/libs/tests/GuestPngDec.cpp b/core/libs/tests/GuestPngDec.cpp
index d75515f8c..6bb53f9f6 100644
--- a/core/libs/tests/GuestPngDec.cpp
+++ b/core/libs/tests/GuestPngDec.cpp
@@ -105,6 +105,13 @@ int main() {
     const PngDecParseParam parsePalette{PALETTE_TRNS, sizeof(PALETTE_TRNS), 0};
     Require(scePngDecParseHeader(&parsePalette, &info) == 0);
     Require(info.color_space == 4 && info.bit_depth == 2 && info.image_flag == 2);
+    for (const std::uint32_t size : {69u, 71u}) {
+        const PngDecParseParam truncatedPalette{PALETTE_TRNS, size, 0};
+        Require(scePngDecParseHeader(&truncatedPalette, &info) == 0);
+        Require(info.color_space == 4 && info.bit_depth == 2 && info.image_flag == 0);
+    }
+    const PngDecParseParam completeTransparency{PALETTE_TRNS, 73, 0};
+    Require(scePngDecParseHeader(&completeTransparency, &info) == 0 && info.image_flag == 2);
     Require(scePngDecParseHeader(nullptr, &info) == invalidParam);
     Require(scePngDecParseHeader(&parse, nullptr) == invalidAddr);
     const PngDecParseParam parseNull{nullptr, 16, 0};