static int xwd_decode_frame(AVCodecContext *avctx, void *data,
                            int *got_frame, AVPacket *avpkt)
{
    AVFrame *p = data;
    const uint8_t *buf = avpkt->data;
    int i, ret, buf_size = avpkt->size;
    uint32_t version, header_size, vclass, ncolors;
    uint32_t xoffset, be, bpp, lsize, rsize;
    uint32_t pixformat, pixdepth, bunit, bitorder, bpad;
    uint32_t rgb[3];
    uint8_t *ptr;
    GetByteContext gb;

    if (buf_size < XWD_HEADER_SIZE)
        return AVERROR_INVALIDDATA;

    bytestream2_init(&gb, buf, buf_size);
    header_size = bytestream2_get_be32u(&gb);

    version = bytestream2_get_be32u(&gb);
    if (version != XWD_VERSION) {
        av_log(avctx, AV_LOG_ERROR, "unsupported version\n");
        return AVERROR_INVALIDDATA;
    }

    if (buf_size < header_size || header_size < XWD_HEADER_SIZE) {
        av_log(avctx, AV_LOG_ERROR, "invalid header size\n");
        return AVERROR_INVALIDDATA;
    }

    pixformat     = bytestream2_get_be32u(&gb);
    pixdepth      = bytestream2_get_be32u(&gb);
    avctx->width  = bytestream2_get_be32u(&gb);
    avctx->height = bytestream2_get_be32u(&gb);
    xoffset       = bytestream2_get_be32u(&gb);
    be            = bytestream2_get_be32u(&gb);
    bunit         = bytestream2_get_be32u(&gb);
    bitorder      = bytestream2_get_be32u(&gb);
    bpad          = bytestream2_get_be32u(&gb);
    bpp           = bytestream2_get_be32u(&gb);
    lsize         = bytestream2_get_be32u(&gb);
    vclass        = bytestream2_get_be32u(&gb);
    rgb[0]        = bytestream2_get_be32u(&gb);
    rgb[1]        = bytestream2_get_be32u(&gb);
    rgb[2]        = bytestream2_get_be32u(&gb);
    bytestream2_skipu(&gb, 8);
    ncolors       = bytestream2_get_be32u(&gb);
    bytestream2_skipu(&gb, header_size - (XWD_HEADER_SIZE - 20));

    av_log(avctx, AV_LOG_DEBUG,
           "pixformat %"PRIu32", pixdepth %"PRIu32", bunit %"PRIu32", bitorder %"PRIu32", bpad %"PRIu32"\n",
           pixformat, pixdepth, bunit, bitorder, bpad);
    av_log(avctx, AV_LOG_DEBUG,
           "vclass %"PRIu32", ncolors %"PRIu32", bpp %"PRIu32", be %"PRIu32", lsize %"PRIu32", xoffset %"PRIu32"\n",
           vclass, ncolors, bpp, be, lsize, xoffset);
    av_log(avctx, AV_LOG_DEBUG,
           "red %0"PRIx32", green %0"PRIx32", blue %0"PRIx32"\n",
           rgb[0], rgb[1], rgb[2]);

    if (pixformat > XWD_Z_PIXMAP) {
        av_log(avctx, AV_LOG_ERROR, "invalid pixmap format\n");
        return AVERROR_INVALIDDATA;
    }

    if (pixdepth == 0 || pixdepth > 32) {
        av_log(avctx, AV_LOG_ERROR, "invalid pixmap depth\n");
        return AVERROR_INVALIDDATA;
    }

    if (xoffset) {
        avpriv_request_sample(avctx, "xoffset %"PRIu32"", xoffset);
        return AVERROR_PATCHWELCOME;
    }

    if (be > 1) {
        av_log(avctx, AV_LOG_ERROR, "invalid byte order\n");
        return AVERROR_INVALIDDATA;
    }

    if (bitorder > 1) {
        av_log(avctx, AV_LOG_ERROR, "invalid bitmap bit order\n");
        return AVERROR_INVALIDDATA;
    }

    if (bunit != 8 && bunit != 16 && bunit != 32) {
        av_log(avctx, AV_LOG_ERROR, "invalid bitmap unit\n");
        return AVERROR_INVALIDDATA;
    }

    if (bpad != 8 && bpad != 16 && bpad != 32) {
        av_log(avctx, AV_LOG_ERROR, "invalid bitmap scan-line pad\n");
        return AVERROR_INVALIDDATA;
    }

    if (bpp == 0 || bpp > 32) {
        av_log(avctx, AV_LOG_ERROR, "invalid bits per pixel\n");
        return AVERROR_INVALIDDATA;
    }

    if (ncolors > 256) {
        av_log(avctx, AV_LOG_ERROR, "invalid number of entries in colormap\n");
        return AVERROR_INVALIDDATA;
    }

    if ((ret = av_image_check_size(avctx->width, avctx->height, 0, NULL)) < 0)
        return ret;

    rsize = FFALIGN(avctx->width * bpp, bpad) / 8;
    if (lsize < rsize) {
        av_log(avctx, AV_LOG_ERROR, "invalid bytes per scan-line\n");
        return AVERROR_INVALIDDATA;
    }

    if (bytestream2_get_bytes_left(&gb) < ncolors * XWD_CMAP_SIZE + (uint64_t)avctx->height * lsize) {
        av_log(avctx, AV_LOG_ERROR, "input buffer too small\n");
        return AVERROR_INVALIDDATA;
    }

    if (pixformat != XWD_Z_PIXMAP) {
        avpriv_report_missing_feature(avctx, "Pixmap format %"PRIu32, pixformat);
        return AVERROR_PATCHWELCOME;
    }

    avctx->pix_fmt = AV_PIX_FMT_NONE;
    switch (vclass) {
    case XWD_STATIC_GRAY:
     case XWD_GRAY_SCALE:
         if (bpp != 1 && bpp != 8)
             return AVERROR_INVALIDDATA;
        if (pixdepth == 1) {
             avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
        } else if (pixdepth == 8) {
             avctx->pix_fmt = AV_PIX_FMT_GRAY8;
         }
         break;
    case XWD_STATIC_COLOR:
    case XWD_PSEUDO_COLOR:
        if (bpp == 8)
            avctx->pix_fmt = AV_PIX_FMT_PAL8;
        break;
    case XWD_TRUE_COLOR:
    case XWD_DIRECT_COLOR:
        if (bpp != 16 && bpp != 24 && bpp != 32)
            return AVERROR_INVALIDDATA;
        if (bpp == 16 && pixdepth == 15) {
            if (rgb[0] == 0x7C00 && rgb[1] == 0x3E0 && rgb[2] == 0x1F)
                avctx->pix_fmt = be ? AV_PIX_FMT_RGB555BE : AV_PIX_FMT_RGB555LE;
            else if (rgb[0] == 0x1F && rgb[1] == 0x3E0 && rgb[2] == 0x7C00)
                avctx->pix_fmt = be ? AV_PIX_FMT_BGR555BE : AV_PIX_FMT_BGR555LE;
        } else if (bpp == 16 && pixdepth == 16) {
            if (rgb[0] == 0xF800 && rgb[1] == 0x7E0 && rgb[2] == 0x1F)
                avctx->pix_fmt = be ? AV_PIX_FMT_RGB565BE : AV_PIX_FMT_RGB565LE;
            else if (rgb[0] == 0x1F && rgb[1] == 0x7E0 && rgb[2] == 0xF800)
                avctx->pix_fmt = be ? AV_PIX_FMT_BGR565BE : AV_PIX_FMT_BGR565LE;
        } else if (bpp == 24) {
            if (rgb[0] == 0xFF0000 && rgb[1] == 0xFF00 && rgb[2] == 0xFF)
                avctx->pix_fmt = be ? AV_PIX_FMT_RGB24 : AV_PIX_FMT_BGR24;
            else if (rgb[0] == 0xFF && rgb[1] == 0xFF00 && rgb[2] == 0xFF0000)
                avctx->pix_fmt = be ? AV_PIX_FMT_BGR24 : AV_PIX_FMT_RGB24;
        } else if (bpp == 32) {
            if (rgb[0] == 0xFF0000 && rgb[1] == 0xFF00 && rgb[2] == 0xFF)
                avctx->pix_fmt = be ? AV_PIX_FMT_ARGB : AV_PIX_FMT_BGRA;
            else if (rgb[0] == 0xFF && rgb[1] == 0xFF00 && rgb[2] == 0xFF0000)
                avctx->pix_fmt = be ? AV_PIX_FMT_ABGR : AV_PIX_FMT_RGBA;
        }
        bytestream2_skipu(&gb, ncolors * XWD_CMAP_SIZE);
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "invalid visual class\n");
        return AVERROR_INVALIDDATA;
    }

    if (avctx->pix_fmt == AV_PIX_FMT_NONE) {
        avpriv_request_sample(avctx,
                              "Unknown file: bpp %"PRIu32", pixdepth %"PRIu32", vclass %"PRIu32"",
                              bpp, pixdepth, vclass);
        return AVERROR_PATCHWELCOME;
    }

    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
        return ret;

    p->key_frame = 1;
    p->pict_type = AV_PICTURE_TYPE_I;

    if (avctx->pix_fmt == AV_PIX_FMT_PAL8) {
        uint32_t *dst = (uint32_t *)p->data[1];
        uint8_t red, green, blue;

        for (i = 0; i < ncolors; i++) {

            bytestream2_skipu(&gb, 4); // skip colormap entry number
            red    = bytestream2_get_byteu(&gb);
            bytestream2_skipu(&gb, 1);
            green  = bytestream2_get_byteu(&gb);
            bytestream2_skipu(&gb, 1);
            blue   = bytestream2_get_byteu(&gb);
            bytestream2_skipu(&gb, 3); // skip bitmask flag and padding

            dst[i] = red << 16 | green << 8 | blue;
        }
    }

    ptr = p->data[0];
    for (i = 0; i < avctx->height; i++) {
        bytestream2_get_bufferu(&gb, ptr, rsize);
        bytestream2_skipu(&gb, lsize - rsize);
        ptr += p->linesize[0];
    }

    *got_frame       = 1;

    return buf_size;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.